I just created a thread in which I needed to upload a small video file, but I found that only image formats were accepted so I had to upload it as a gif (I wanted to not rely on some 3rd party service).
This might make sense on the surface, however I can think of a lot of perfectly legitimate use cases for other file types that don't use appreciably more space than simply image files. One such case is the aforementioned video upload -- the .webm file was higher quality and just 12 KiBs while the gif was lower quality and 40KiBs. Another example is one might want to share a complete Rust project as a zip file -- this is just text files, so it's small and thus easy to store (and a whole git repository is often excessive), but it would be blocked now.
As such, I propose that a limit of file size is imposed, and that the type is allowed to be anything (even something like executable files that could be malicious is probably fine since users on this forum are very likely to know the risk of taking various actions with these types of files). One might say to simply store the files elsewhere and link them, but the problem there is that the link will likely eventually go dead before the forum does. Stack Overflow has some advice to this end ("Provide context for links" under this page).