Default user image and cover

closes #812

- replace defaults with consistently named .png files
- change the settings saving code so that it doesn't double-save images and save the defaults to the db

core/client/assets/sass/layouts/users.scss

@@ -208,7 +208,7 @@
             display: block;
             width: 100%;
             height: 100%;
-            background-image: url(/shared/img/default-user-profile-picture.jpg);
+            background-image: url(/shared/img/user-image.png);
             background-size: cover;
             background-position: center center;
         }

core/client/tpl/settings/user-profile.hbs

@@ -9,7 +9,7 @@
 <section class="content no-padding">
 
     <header class="user-profile-header">
-        <img id="user-cover" class="cover-image" src="{{#if cover}}{{cover}}{{else}}/shared/img/cover.png{{/if}}" title="{{name}}'s Cover Image"/>
+        <img id="user-cover" class="cover-image" src="{{#if cover}}{{cover}}{{else}}/shared/img/user-cover.png{{/if}}" title="{{name}}'s Cover Image"/>
         <button class="edit-cover-image js-modal-cover">Change Cover</button>
     </header>
 

core/client/views/settings.js

@@ -180,8 +180,6 @@
                 this.model.save({
                     title: title,
                     description: description,
-                    logo: this.$('#blog-logo').attr("src"),
-                    cover: this.$('#blog-cover').attr("src"),
                     email: email,
                     postsPerPage: postsPerPage,
                     activeTheme: this.$('#activeTheme').val()
@@ -320,9 +318,7 @@
                     'email':            userEmail,
                     'location':         userLocation,
                     'website':          userWebsite,
-                    'bio':              userBio,
-                    'image':            this.$('#user-image').attr('src'),
-                    'cover':            this.$('#user-cover').attr('src')
+                    'bio':              userBio
                 }, {
                     success: this.saveSuccess,
                     error: this.saveError

core/server/views/partials/navbar.hbs

@@ -9,7 +9,7 @@
 
             <li id="usermenu" class="subnav">
                 <a href="#" data-toggle="ul" class="dropdown">
-                    <img class="avatar" src="{{#if currentUser.profile}}{{currentUser.profile}}{{else}}/shared/img/default-user-profile-picture.jpg{{/if}}" alt="Avatar" />
+                    <img class="avatar" src="{{#if currentUser.profile}}{{currentUser.profile}}{{else}}/shared/img/user-image.png{{/if}}" alt="Avatar" />
                     <span class="name">{{#if currentUser.name}}{{currentUser.name}}{{else}}Ghost{{/if}} v{{version}}</span>
                 </a>
                 <ul class="overlay">