diff --git a/ghost/admin/app/components/gh-file-uploader.js b/ghost/admin/app/components/gh-file-uploader.js
index 7aff070130..45bb95328b 100644
--- a/ghost/admin/app/components/gh-file-uploader.js
+++ b/ghost/admin/app/components/gh-file-uploader.js
@@ -198,16 +198,10 @@ export default Component.extend({
     },
 
     _defaultValidator(file) {
-        let accept = this._accept;
+        let [, extension] = (/(?:\.([^.]+))?$/).exec(file.name);
+        let extensions = this._extensions;
 
-        if (isBlank(file.type)) {
-            let [, extension] = (/(?:\.([^.]+))?$/).exec(file.name);
-            let extensions = this._extensions;
-
-            if (!extension || extensions.indexOf(extension.toLowerCase()) === -1) {
-                return new UnsupportedMediaTypeError();
-            }
-        } else if (!isBlank(file.type) && !isBlank(accept) && file && accept.indexOf(file.type) === -1) {
+        if (!extension || extensions.indexOf(extension.toLowerCase()) === -1) {
             return new UnsupportedMediaTypeError();
         }
 
diff --git a/ghost/admin/app/components/gh-image-uploader.js b/ghost/admin/app/components/gh-image-uploader.js
index b1bf5abb1c..199a3af937 100644
--- a/ghost/admin/app/components/gh-image-uploader.js
+++ b/ghost/admin/app/components/gh-image-uploader.js
@@ -3,6 +3,7 @@ import computed from 'ember-computed';
 import injectService from 'ember-service/inject';
 import {htmlSafe} from 'ember-string';
 import {isBlank} from 'ember-utils';
+import {isEmberArray} from 'ember-array/utils';
 import run from 'ember-runloop';
 
 import {invokeAction} from 'ember-invoke-action';
@@ -24,6 +25,7 @@ export default Component.extend({
     altText: '',
     saveButton: true,
     accept: 'image/gif,image/jpg,image/jpeg,image/png,image/svg+xml',
+    extensions: ['gif', 'jpg', 'jpeg', 'png', 'svg'],
     validate: null,
 
     dragClass: null,
@@ -212,9 +214,14 @@ export default Component.extend({
     },
 
     _defaultValidator(file) {
-        let accept = this.get('accept');
+        let extensions = this.get('extensions');
+        let [, extension] = (/(?:\.([^.]+))?$/).exec(file.name);
 
-        if (!isBlank(accept) && file && accept.indexOf(file.type) === -1) {
+        if (!isEmberArray(extensions)) {
+            extensions = extensions.split(',');
+        }
+
+        if (!extension || extensions.indexOf(extension.toLowerCase()) === -1) {
             return new UnsupportedMediaTypeError();
         }
 
diff --git a/ghost/admin/app/components/modals/upload-theme.js b/ghost/admin/app/components/modals/upload-theme.js
index 1c162b1e89..184d7e6607 100644
--- a/ghost/admin/app/components/modals/upload-theme.js
+++ b/ghost/admin/app/components/modals/upload-theme.js
@@ -6,13 +6,13 @@ import {
     UnsupportedMediaTypeError,
     isThemeValidationError
 } from 'ghost-admin/services/ajax';
-import {isBlank} from 'ember-utils';
 import run from 'ember-runloop';
 import injectService from 'ember-service/inject';
 
 export default ModalComponent.extend({
 
     accept: ['application/zip', 'application/x-zip-compressed'],
+    extensions: ['zip'],
     availableThemes: null,
     closeDisabled: false,
     file: null,
@@ -47,13 +47,15 @@ export default ModalComponent.extend({
 
     actions: {
         validateTheme(file) {
-            let accept = this.get('accept');
             let themeName = file.name.replace(/\.zip$/, '');
             let availableThemeNames = this.get('availableThemeNames');
 
             this.set('file', file);
 
-            if (!isBlank(accept) && file && accept.indexOf(file.type) === -1) {
+            let [, extension] = (/(?:\.([^.]+))?$/).exec(file.name);
+            let extensions = this.get('extensions');
+
+            if (!extension || extensions.indexOf(extension.toLowerCase()) === -1) {
                 return new UnsupportedMediaTypeError();
             }
 
diff --git a/ghost/admin/tests/acceptance/subscribers-test.js b/ghost/admin/tests/acceptance/subscribers-test.js
index c076461a4f..839b9ceb53 100644
--- a/ghost/admin/tests/acceptance/subscribers-test.js
+++ b/ghost/admin/tests/acceptance/subscribers-test.js
@@ -246,7 +246,7 @@ describe('Acceptance: Subscribers', function() {
             });
 
             click('.btn:contains("Import CSV")');
-            fileUpload('.fullscreen-modal input[type="file"]', ['test'], {type: 'text/csv'});
+            fileUpload('.fullscreen-modal input[type="file"]', ['test'], {name: 'test.csv'});
 
             andThen(function () {
                 // modal title changes
diff --git a/ghost/admin/tests/acceptance/version-mismatch-test.js b/ghost/admin/tests/acceptance/version-mismatch-test.js
index d08e8e3bcf..51292f68b3 100644
--- a/ghost/admin/tests/acceptance/version-mismatch-test.js
+++ b/ghost/admin/tests/acceptance/version-mismatch-test.js
@@ -104,7 +104,7 @@ describe('Acceptance: Version Mismatch', function() {
 
             visit('/subscribers');
             click('.btn:contains("Import CSV")');
-            fileUpload('.fullscreen-modal input[type="file"]', ['test'], {type: 'text/csv'});
+            fileUpload('.fullscreen-modal input[type="file"]', ['test'], {name: 'test.csv'});
 
             andThen(() => {
                 // alert is shown
diff --git a/ghost/admin/tests/integration/components/gh-file-uploader-test.js b/ghost/admin/tests/integration/components/gh-file-uploader-test.js
index 51d78f9eb1..3f49fa2770 100644
--- a/ghost/admin/tests/integration/components/gh-file-uploader-test.js
+++ b/ghost/admin/tests/integration/components/gh-file-uploader-test.js
@@ -91,7 +91,7 @@ describeComponent(
             stubSuccessfulUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(server.handledRequests.length).to.equal(1);
@@ -107,7 +107,7 @@ describeComponent(
             stubSuccessfulUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadSuccess=(action uploadSuccess)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(uploadSuccess.calledOnce).to.be.true;
@@ -123,7 +123,7 @@ describeComponent(
             stubFailedUpload(server, 500);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadSuccess=(action uploadSuccess)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(uploadSuccess.calledOnce).to.be.false;
@@ -138,7 +138,7 @@ describeComponent(
             stubSuccessfulUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl fileSelected=(action fileSelected)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(fileSelected.calledOnce).to.be.true;
@@ -154,7 +154,7 @@ describeComponent(
             stubSuccessfulUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadStarted=(action uploadStarted)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(uploadStarted.calledOnce).to.be.true;
@@ -169,7 +169,7 @@ describeComponent(
             stubSuccessfulUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadFinished=(action uploadFinished)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(uploadFinished.calledOnce).to.be.true;
@@ -184,7 +184,7 @@ describeComponent(
             stubFailedUpload(server);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadFinished=(action uploadFinished)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(uploadFinished.calledOnce).to.be.true;
@@ -195,7 +195,7 @@ describeComponent(
         it('displays invalid file type error', function (done) {
             stubFailedUpload(server, 415, 'UnsupportedMediaTypeError');
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -209,7 +209,7 @@ describeComponent(
         it('displays file too large for server error', function (done) {
             stubFailedUpload(server, 413, 'RequestEntityTooLargeError');
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -223,7 +223,7 @@ describeComponent(
                 return [413, {}, ''];
             });
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -235,7 +235,7 @@ describeComponent(
         it('displays other server-side error with message', function (done) {
             stubFailedUpload(server, 400, 'UnknownError');
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -249,7 +249,7 @@ describeComponent(
                 return [500, {'Content-Type': 'application/json'}, ''];
             });
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -265,7 +265,7 @@ describeComponent(
             stubFailedUpload(server, 400, 'VersionMismatchError');
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(showAPIError.calledOnce).to.be.true;
@@ -279,7 +279,7 @@ describeComponent(
 
             stubFailedUpload(server, 400, 'UnknownError');
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(showAPIError.called).to.be.false;
@@ -290,7 +290,7 @@ describeComponent(
         it('can be reset after a failed upload', function (done) {
             stubFailedUpload(server, 400, 'UnknownError');
             this.render(hbs`{{gh-file-uploader url=uploadUrl}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 run(() => {
@@ -311,7 +311,7 @@ describeComponent(
             stubSuccessfulUpload(server, 150);
 
             this.render(hbs`{{gh-file-uploader url=uploadUrl uploadFinished=(action done)}}`);
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             // after 75ms we should have had one progress event
             run.later(this, function () {
@@ -347,7 +347,7 @@ describeComponent(
             let uploadSuccess = sinon.spy();
             let drop = $.Event('drop', {
                 dataTransfer: {
-                    files: [createFile(['test'], {type: 'text/csv'})]
+                    files: [createFile(['test'], {name: 'test.csv'})]
                 }
             });
 
@@ -367,7 +367,7 @@ describeComponent(
             });
         });
 
-        it('validates "accept" mime type by default', function (done) {
+        it('validates extension by default', function (done) {
             let uploadSuccess = sinon.spy();
             let uploadFailed = sinon.spy();
 
@@ -381,7 +381,7 @@ describeComponent(
                 uploadSuccess=(action uploadSuccess)
                 uploadFailed=(action uploadFailed)}}`);
 
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'application/plain'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.txt'});
 
             wait().then(() => {
                 expect(uploadSuccess.called).to.be.false;
@@ -406,7 +406,7 @@ describeComponent(
                 uploadSuccess=(action uploadSuccess)
                 validate=(action validate)}}`);
 
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(validate.calledOnce).to.be.true;
@@ -432,7 +432,7 @@ describeComponent(
                 uploadFailed=(action uploadFailed)
                 validate=(action validate)}}`);
 
-            fileUpload(this.$('input[type="file"]'), ['test'], {type: 'text/csv'});
+            fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.csv'});
 
             wait().then(() => {
                 expect(validate.calledOnce).to.be.true;
diff --git a/ghost/admin/tests/integration/components/gh-image-uploader-test.js b/ghost/admin/tests/integration/components/gh-image-uploader-test.js
index d5f0db8a33..21591a1208 100644
--- a/ghost/admin/tests/integration/components/gh-image-uploader-test.js
+++ b/ghost/admin/tests/integration/components/gh-image-uploader-test.js
@@ -145,7 +145,7 @@ describeComponent(
                 stubSuccessfulUpload(server);
 
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(server.handledRequests.length).to.equal(1);
@@ -161,7 +161,7 @@ describeComponent(
                 this.get('sessionService').set('isAuthenticated', true);
 
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     let [request] = server.handledRequests;
@@ -177,7 +177,7 @@ describeComponent(
                 stubSuccessfulUpload(server);
 
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(update.calledOnce).to.be.true;
@@ -193,7 +193,7 @@ describeComponent(
                 stubFailedUpload(server, 500);
 
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(update.calledOnce).to.be.false;
@@ -208,7 +208,7 @@ describeComponent(
                 stubSuccessfulUpload(server);
 
                 this.render(hbs`{{gh-image-uploader url=image fileSelected=(action fileSelected) update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(fileSelected.calledOnce).to.be.true;
@@ -224,7 +224,7 @@ describeComponent(
                 stubSuccessfulUpload(server);
 
                 this.render(hbs`{{gh-image-uploader image=image uploadStarted=(action uploadStarted) update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(uploadStarted.calledOnce).to.be.true;
@@ -239,7 +239,7 @@ describeComponent(
                 stubSuccessfulUpload(server);
 
                 this.render(hbs`{{gh-image-uploader image=image uploadFinished=(action uploadFinished) update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(uploadFinished.calledOnce).to.be.true;
@@ -254,7 +254,7 @@ describeComponent(
                 stubFailedUpload(server);
 
                 this.render(hbs`{{gh-image-uploader image=image uploadFinished=(action uploadFinished) update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(uploadFinished.calledOnce).to.be.true;
@@ -265,7 +265,7 @@ describeComponent(
             it('displays invalid file type error', function (done) {
                 stubFailedUpload(server, 415, 'UnsupportedMediaTypeError');
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -279,7 +279,7 @@ describeComponent(
             it('displays file too large for server error', function (done) {
                 stubFailedUpload(server, 413, 'RequestEntityTooLargeError');
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -293,7 +293,7 @@ describeComponent(
                     return [413, {}, ''];
                 });
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -305,7 +305,7 @@ describeComponent(
             it('displays other server-side error with message', function (done) {
                 stubFailedUpload(server, 400, 'UnknownError');
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -319,7 +319,7 @@ describeComponent(
                     return [500, {'Content-Type': 'application/json'}, ''];
                 });
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(this.$('.failed').length, 'error message is displayed').to.equal(1);
@@ -335,7 +335,7 @@ describeComponent(
                 stubFailedUpload(server, 400, 'VersionMismatchError');
 
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(showAPIError.calledOnce).to.be.true;
@@ -349,7 +349,7 @@ describeComponent(
 
                 stubFailedUpload(server, 400, 'UnknownError');
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(showAPIError.called).to.be.false;
@@ -360,7 +360,7 @@ describeComponent(
             it('can be reset after a failed upload', function (done) {
                 stubFailedUpload(server, 400, 'UnknownError');
                 this.render(hbs`{{gh-image-uploader image=image update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'test.png'});
 
                 wait().then(() => {
                     run(() => {
@@ -381,7 +381,7 @@ describeComponent(
                 stubSuccessfulUpload(server, 150);
 
                 this.render(hbs`{{gh-image-uploader image=image uploadFinished=(action done) update=(action update)}}`);
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 // after 75ms we should have had one progress event
                 run.later(this, function () {
@@ -419,7 +419,7 @@ describeComponent(
                 let uploadSuccess = sinon.spy();
                 let drop = $.Event('drop', {
                     dataTransfer: {
-                        files: [createFile(['test'], {type: 'image/png'})]
+                        files: [createFile(['test'], {name: 'test.png'})]
                     }
                 });
 
@@ -439,7 +439,7 @@ describeComponent(
                 });
             });
 
-            it('validates "accept" mime type by default', function (done) {
+            it('validates extension by default', function (done) {
                 let uploadSuccess = sinon.spy();
                 let uploadFailed = sinon.spy();
 
@@ -452,7 +452,7 @@ describeComponent(
                     uploadSuccess=(action uploadSuccess)
                     uploadFailed=(action uploadFailed)}}`);
 
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'application/plain'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.json'});
 
                 wait().then(() => {
                     expect(uploadSuccess.called).to.be.false;
@@ -476,7 +476,7 @@ describeComponent(
                     uploadSuccess=(action uploadSuccess)
                     validate=(action validate)}}`);
 
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'application/plain'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.txt'});
 
                 wait().then(() => {
                     expect(validate.calledOnce).to.be.true;
@@ -501,7 +501,7 @@ describeComponent(
                     uploadFailed=(action uploadFailed)
                     validate=(action validate)}}`);
 
-                fileUpload(this.$('input[type="file"]'), ['test'], {type: 'image/png'});
+                fileUpload(this.$('input[type="file"]'), ['test'], {name: 'test.png'});
 
                 wait().then(() => {
                     expect(validate.calledOnce).to.be.true;