diff --git a/Makefile.inputs b/Makefile.inputs
index 51804c3..240a8fb 100644
--- a/Makefile.inputs
+++ b/Makefile.inputs
@@ -6,6 +6,7 @@ export ARCH                    := x86_64
 export EXTRA_BOOT_PARAMS       :=
 export IMAGE_NAME              := base
 export IMAGE_REPO              := quay.io/fedora-ostree-desktops
+export IMAGE_SRC                = docker://$(IMAGE_REPO)/$(IMAGE_NAME):$(IMAGE_TAG)
 export IMAGE_TAG                = $(VERSION)
 export IMAGE_SIGNED            := true
        REPOS                   := $(subst :,\:,$(wildcard /etc/yum.repos.d/*.repo))
diff --git a/README.md b/README.md
index 0124d58..f02f36d 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,7 @@ The following variables can be used to customize the created ISO.
 | image_name              | Name of the source container image                                           | base                                         | :white_check_mark: | :white_check_mark: |
 | image_repo              | Repository containing the source container image                             | quay.io/fedora-ostree-desktops               | :white_check_mark: | :white_check_mark: |
 | image_signed            | Whether the container image is signed. The policy to test the signing must be configured inside the container image | true  | :white_check_mark: | :white_check_mark: |
+| image_src               | Overrides the source of the container image. Must be formatted for the skopeo copy command | docker://*IMAGE_REPO*/*IMAGE_NAME*:*IMAGE_TAG*  | :white_check_mark: | :white_check_mark: |
 | image_tag               | Tag of the source container image                                            | *VERSION*                                    | :white_check_mark: | :white_check_mark: |
 | iso_name                | Name of the ISO you wish to output when completed                            | build/deploy.iso                             | :white_check_mark: | :white_check_mark: |
 | make_target             | Overrides the default make target                                            | *ISO_NAME*-Checksum                          | :white_check_mark: | :x:                |
diff --git a/action.yml b/action.yml
index e325527..5313d1b 100644
--- a/action.yml
+++ b/action.yml
@@ -63,6 +63,9 @@ inputs:
     description: Whether the container image is signed. The policy to test the signing must be configured inside the container image
     required: false
     default: "true"
+  image_src:
+    description: Overrides the source of the container image. Must be formatted for the skopeo copy command
+    required: false
   image_tag:
     description: Tag of the source container image. Defaults to the installer version
     required: false
diff --git a/container/Makefile b/container/Makefile
index 88024a0..c4467af 100644
--- a/container/Makefile
+++ b/container/Makefile
@@ -1,5 +1,5 @@
 $(IMAGE_NAME)-$(IMAGE_TAG):
-	skopeo copy docker://$(IMAGE_REPO)/$(IMAGE_NAME):$(IMAGE_TAG) oci:$(IMAGE_NAME)-$(IMAGE_TAG)
+	skopeo copy $(IMAGE_SRC) oci:$(IMAGE_NAME)-$(IMAGE_TAG)
 
 install-deps:
 	$(install_pkg) skopeo