Inconsistency in GIF extension cases causes issues in Discord

[JewinV]

Describe the bug
When using the neko.py API to retrieve GIFs, some of the returned links have their file extensions in uppercase (.GIF). Discord, however, treats these links as static images instead of animated GIFs.

Expected behavior
All GIF links should have their file extensions in lowercase (.gif) to ensure consistent handling across all platforms, including Discord.

Steps to Reproduce

1. Use the neko.py API to request GIFs.
2. Receive a link with the GIF extension in uppercase (.GIF).
3. Post this link in a Discord chat.
4. Notice that Discord displays the image as a static image, not an animated GIF.

Possible Solution
Ensure all GIF links returned by the neko.py API have their file extensions in lowercase (.gif). This could involve modifying the process which provides these links to change the case of the file extension to lowercase before returning it.

Additional context
The behavior is inconsistent. Not all GIF links have their extensions in uppercase, but for the ones that do, they are not properly rendered as animated GIFs in Discord.