diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 741213e..6602911 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -1,11 +1,9 @@
 name: Unit tests
 on:
-  push:
-    branches:
-      - 'main'
   pull_request:
+  push:
     branches:
-      - 'main'
+      - main
 
 jobs:
   check-go:
@@ -93,7 +91,7 @@ jobs:
         run: |
           sudo --non-interactive --shell <<END_SUDO
             install -d -m 0750 -o root -g docker /run/buildkit
-            buildkitd &
+            buildkitd --oci-worker-snapshotter=stargz &
             while ! test -S /run/buildkit/buildkitd.sock; do sleep 0.1; done
             chgrp docker /run/buildkit/buildkitd.sock
           END_SUDO
diff --git a/pkg/dazzle/build.go b/pkg/dazzle/build.go
index 885f2e0..8ceee1f 100644
--- a/pkg/dazzle/build.go
+++ b/pkg/dazzle/build.go
@@ -500,8 +500,11 @@ func (p *ProjectChunk) buildAsBase(ctx context.Context, dest reference.Named, se
 				{
 					Type: "image",
 					Attrs: map[string]string{
-						"name": dest.String(),
-						"push": "true",
+						"name":              dest.String(),
+						"push":              "true",
+						"compression":       "estargz",
+						"oci-mediatypes":    "true",
+						"force-compression": "true",
 					},
 				},
 			},
@@ -685,8 +688,11 @@ func (p *ProjectChunk) buildImage(ctx context.Context, tpe ChunkImageType, sess
 				{
 					Type: "image",
 					Attrs: map[string]string{
-						"name": tgt.String(),
-						"push": "true",
+						"name":              tgt.String(),
+						"push":              "true",
+						"compression":       "estargz",
+						"oci-mediatypes":    "true",
+						"force-compression": "true",
 					},
 				},
 			},