diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5eaaf1df..2f028266 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -40,6 +40,16 @@ jobs:
       - uses: actions/checkout@v2
         with:
           fetch-depth: 0  # Need full history for voom like versions
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Docker Build/Push
+        run: |
+          export ${{ matrix.IMPL }}
+          ./ci.sh docker-build-push ${IMPL}
       - name: Build
         run: |
           export ${{ matrix.IMPL }}
diff --git a/Makefile b/Makefile
index acad2220..ff1cd7a6 100644
--- a/Makefile
+++ b/Makefile
@@ -126,7 +126,7 @@ STEP_TEST_FILES = $(strip $(wildcard \
 
 # DOCKERIZE utility functions
 lc = $(subst A,a,$(subst B,b,$(subst C,c,$(subst D,d,$(subst E,e,$(subst F,f,$(subst G,g,$(subst H,h,$(subst I,i,$(subst J,j,$(subst K,k,$(subst L,l,$(subst M,m,$(subst N,n,$(subst O,o,$(subst P,p,$(subst Q,q,$(subst R,r,$(subst S,s,$(subst T,t,$(subst U,u,$(subst V,v,$(subst W,w,$(subst X,x,$(subst Y,y,$(subst Z,z,$1))))))))))))))))))))))))))
-impl_to_image = kanaka/mal-test-$(call lc,$(1)):$(shell ./voom-like-version.sh impls/$(1)/Dockerfile)
+impl_to_image = ghcr.io/kanaka/mal-test-$(call lc,$(1)):$(shell ./voom-like-version.sh impls/$(1)/Dockerfile)
 
 actual_impl = $(if $(filter mal,$(1)),$(patsubst %-mal,%,$(MAL_IMPL)),$(1))
 
diff --git a/ci.sh b/ci.sh
index 5885ae67..ff096ed0 100755
--- a/ci.sh
+++ b/ci.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -ex
 
@@ -24,11 +24,23 @@ mode_var=${raw_mode_var/-/__}
 mode_var=${mode_var/./__}
 mode_val=${!mode_var}
 
-MAKE="make ${mode_val:+${mode_var}=${mode_val}}"
-
 log_prefix="${ACTION}${REGRESS:+-regress}-${IMPL}${mode_val:+-${mode_val}}${MAL_IMPL:+-${MAL_IMPL}}"
 TEST_OPTS="${TEST_OPTS} --debug-file ../../${log_prefix}.debug"
 
+img_base="${MAL_IMPL:-${IMPL}}"
+img_impl="${img_base%%-mal}"
+img_name="mal-test-${img_impl,,}"
+img_ver=$(./voom-like-version.sh impls/${img_impl}/Dockerfile)
+IMAGE="ghcr.io/kanaka/${img_name}:${img_ver}"
+
+# If NO_DOCKER is blank then run make in a docker image
+MAKE="make ${mode_val:+${mode_var}=${mode_val}}"
+if [ -z "${NO_DOCKER}" ]; then
+    # We could just use make DOCKERIZE=1 instead but that does add
+    # non-trivial startup overhead for each step.
+    MAKE="docker run -i -u $(id -u) -v `pwd`:/mal ${IMAGE} ${MAKE}"
+fi
+
 # Log everything below this point:
 exec &> >(tee ./${log_prefix}.log)
 
@@ -47,18 +59,18 @@ echo "IMPL: ${IMPL}"
 echo "BUILD_IMPL: ${BUILD_IMPL}"
 echo "MAL_IMPL: ${MAL_IMPL}"
 echo "TEST_OPTS: ${TEST_OPTS}"
-
-# If NO_DOCKER is blank then launch use a docker image, otherwise use
-# the Travis/Github Actions image/tools directly.
-if [ -z "${NO_DOCKER}" ]; then
-    img_impl=$(echo "${MAL_IMPL:-${IMPL}}" | tr '[:upper:]' '[:lower:]')
-    img_ver=$(./voom-like-version.sh impls/${img_impl}/Dockerfile)
-    # We could just use make DOCKERIZE=1 instead but that does add
-    # non-trivial startup overhead for each step.
-    MAKE="docker run -i -u $(id -u) -v `pwd`:/mal kanaka/mal-test-${img_impl%%-mal}:${img_ver} ${MAKE}"
-fi
+echo "IMAGE: ${IMAGE}"
+echo "MAKE: ${MAKE}"
 
 case "${ACTION}" in
+docker-build-push)
+    if ! docker pull ${IMAGE}; then
+        make "docker-build^${MAL_IMPL:-${IMPL}}"
+        if [ "${GITHUB_REF}" = "refs/heads/main" ]; then
+            docker push ${IMAGE}
+        fi
+    fi
+    ;;
 build)
     # rpython often fails on step9 in compute_vars_longevity
     # so build step9, then continue with the full build