I wasn't able to find a wiki page (or somewhere else) an offical answer on file limits.

It would be good if one was added somewhere along the upload section.

From googling I found the following:

• Images:
• 10MB file size
• Width or Height limit of 15.000px

• Videos:
• 100MB file size

What else, and/or different?

howto:sites_and_sources#table

So, JPEG and PNG images are 100 MB or 15000×15000 resolution, whichever comes first.
GIF just 20MB (no 15k px?)
100 MB for flash
And WebM 100 MB

JPEG, PNG, 100 MB. GIF, 20 MB. 15000×15000 resolution.

(from the E621 entry of the table Mairo linked)

Personally I would read that as '15000x15000 limit applies to all image files. JPEG and PNG get 100mb, GIF gets 20mb'

The table does leave ambiguous whether the 15000x15000 limit applies to WebMs. WebM itself has a 16384x16384 limit, if it uses VP8 codec, or 65536x65536 limit, if it uses VP9 codec.

savageorange said:
(from the E621 entry of the table Mairo linked)

Personally I would read that as '15000x15000 limit applies to all image files. JPEG and PNG get 100mb, GIF gets 20mb'

Yes.

savageorange said:
The table does leave ambiguous whether the 15000x15000 limit applies to WebMs. WebM itself has a 16384x16384 limit, if it uses VP8 codec, or 65536x65536 limit, if it uses VP9 codec.

Because I have not tested what could be maximum resolution and for most people even 4K video files which we do have is too much. Also haven't asked about it. Right now I would assume the limit to be the same with images, as filesize limit change from 50 MB -> 100 MB also effected all uploaded files.