Did you by any chance build these images locally and pushed them directly to the Fly registry?
Images uploaded this way can be used to deploy (referred to by tag, for example) but they won’t show in registry or releases unless they were built as part of a fly deploy run; this is because only a fly deploy-generated image is tracked in the database that powers registry and releases. Data here does not come directly from the Fly registry (despite the /registry URL) - Docker registries don’t usually provide a list of images in them, they’re more of a tag → image referenceable store.
- Daniel