Bad error message when config.yaml is missing the 'image' key

[f18m]

I noticed that when I try to use the builder to build the container image for my addon, if config.yaml is missing the 'image' key, I get a weird error message at some point saying:

10:36:29] INFO: Setup crosscompiling feature
[10:36:29] WARNING: Can't enable crosscompiling feature
[10:36:29] INFO: Starting docker.
[10:36:29] INFO: Waiting for docker to initialize...
[10:36:30] INFO: Docker was initialized
[10:36:30] INFO: Run addon build for: armhf armv7 amd64 i386 aarch64
[10:36:30] INFO: Init cache for /:0.0.1 with tag latest and platform linux/amd64
[10:36:30] INFO: Init cache for /:0.0.1 with tag latest and platform linux/arm/v6
[10:36:30] INFO: Init cache for /:0.0.1 with tag latest and platform linux/386
[10:36:30] INFO: Init cache for /:0.0.1 with tag latest and platform linux/arm/v7
[10:36:30] INFO: Init cache for /:0.0.1 with tag latest and platform linux/arm64
[10:36:30] WARNING: No cache image found. Disabling cache for this build.
[10:36:30] WARNING: No cache image found. Disabling cache for this build.
[10:36:30] WARNING: No cache image found. Disabling cache for this build.
[10:36:30] WARNING: No cache image found. Disabling cache for this build.
[10:36:30] WARNING: No cache image found. Disabling cache for this build.
[10:36:30] INFO: Run build for /:0.0.1 with platform linux/arm/v7
[10:36:30] INFO: Run build for /:0.0.1 with platform linux/386
[10:36:30] INFO: Run build for /:0.0.1 with platform linux/arm/v6
[10:36:30] INFO: Run build for /:0.0.1 with platform linux/amd64
[10:36:30] INFO: Run build for /:0.0.1 with platform linux/arm64
ERROR: invalid tag "/:0.0.1": invalid reference format
ERROR: invalid tag "/:0.0.1": invalid reference format
ERROR: invalid tag "/:0.0.1": invalid reference format
ERROR: invalid tag "/:0.0.1": invalid reference format
ERROR: invalid tag "/:0.0.1": invalid reference format

I think builder should validate if it has all the info needed BEFORE trying to kick off the build, and give a readable error message if not