Lemmy Connect attempts to add ?format=webp to the image URL when loading .gif image, this makes many Lemmy servers return an error.
When opening the post in the web browser, without the extra addition to the image URL, the image loads correctly.
Post where the bug is present: https://lemmy.world/post/19556846
I’m not saying that Connect shouldn’t be updated to address this, but that does seem more like a Lemmy bug than a Connect bug. The presence of extra query parameters shouldn’t (IMO) be breaking an API request, they should just be ignored.