diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 03bd00b0e4ac0acd7646c89d7b0ace158894e7a1..1cb589634c689a52796b104811c87fd92ee511f9 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -8,7 +8,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/fmt.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/fmt.sh
 
@@ -17,7 +17,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/lint.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/lint.sh
 
@@ -26,7 +26,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/test.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/test.sh
 
@@ -35,7 +35,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/release.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/release.sh
       - name: Upload npm package artifact
@@ -55,7 +55,7 @@ jobs:
           name: npm-package
           path: ./release-npm-package
       - name: Run ./ci/steps/release-packages.sh
-        uses: ./ci/images/centos:7
+        uses: ./ci/images/centos7
         with:
           args: ./ci/steps/release-packages.sh
       - name: Upload release artifacts
@@ -75,7 +75,7 @@ jobs:
           name: npm-package
           path: ./release-npm-package
       - name: Run ./ci/steps/release-packages.sh
-        uses: ./ci/images/centos:7
+        uses: ./ci/images/centos7
         with:
           args: ./ci/steps/release-packages.sh
       - name: Upload release artifacts
@@ -116,7 +116,7 @@ jobs:
           name: release-packages
           path: ./release-packages
       - name: Run ./ci/steps/build-docker-image.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/build-docker-image.sh
       - name: Upload release image
@@ -136,7 +136,7 @@ jobs:
           name: release-packages
           path: ./release-packages
       - name: Run ./ci/steps/build-docker-image.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/build-docker-image.sh
       - name: Upload release image
diff --git a/.github/workflows/publish.yaml b/.github/workflows/publish.yaml
index 0eede125d237d622b49877577a358ac00df1c24a..c2fe429b9a7bfa52d65f8ce663c2697e217df413 100644
--- a/.github/workflows/publish.yaml
+++ b/.github/workflows/publish.yaml
@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/publish-npm.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/publish-npm.sh
         env:
@@ -22,7 +22,7 @@ jobs:
     steps:
       - uses: actions/checkout@v1
       - name: Run ./ci/steps/push-docker-manifest.sh
-        uses: ./ci/images/debian:8
+        uses: ./ci/images/debian8
         with:
           args: ./ci/steps/push-docker-manifest.sh
         env:
diff --git a/ci/dev/lint.sh b/ci/dev/lint.sh
index 72de463e1e69cef2c5b3ab8dd335234687f95d36..1d793717c1d56ba536259d9a6f2d54f861cb3001 100755
--- a/ci/dev/lint.sh
+++ b/ci/dev/lint.sh
@@ -7,7 +7,7 @@ main() {
   eslint --max-warnings=0 --fix $(git ls-files "*.ts" "*.tsx" "*.js")
   stylelint $(git ls-files "*.css")
   tsc --noEmit
-  # See comment in ./ci/image/debian:8
+  # See comment in ./ci/image/debian8
   if [[ ! ${CI-} ]]; then
     shellcheck -e SC2046,SC2164,SC2154,SC1091,SC1090 $(git ls-files "*.sh")
   fi
diff --git a/ci/images/centos:7/Dockerfile b/ci/images/centos7/Dockerfile
similarity index 100%
rename from ci/images/centos:7/Dockerfile
rename to ci/images/centos7/Dockerfile
diff --git a/ci/images/debian:8/Dockerfile b/ci/images/debian8/Dockerfile
similarity index 100%
rename from ci/images/debian:8/Dockerfile
rename to ci/images/debian8/Dockerfile
diff --git a/doc/CONTRIBUTING.md b/doc/CONTRIBUTING.md
index 706a56485a9e3e3f943cfc1cfef43f7471eaea6f..219e484618e3723a57a7c2cf45ee898ad2a791bb 100644
--- a/doc/CONTRIBUTING.md
+++ b/doc/CONTRIBUTING.md
@@ -21,7 +21,7 @@ Differences:
 - We require a minimum of node v12 but later versions should work.
 - We use [fnpm](https://github.com/goreleaser/nfpm) to build `.deb` and `.rpm` packages.
 - We use [jq](https://stedolan.github.io/jq/) to build code-server releases.
-- The [CI container](../ci/images/debian:8/Dockerfile) is a useful reference for all our dependencies.
+- The [CI container](../ci/images/debian8/Dockerfile) is a useful reference for all our dependencies.
 
 ## Development Workflow