On my upload page it shows

[blockquote]
This web-based upload accepts the file formats: BMP, GIF, PNG, 3GP, FLV, MOV, MP3, MP4, and ZIP.
[/blockquote]

What about jpg/jpeg? Why can't I upload jpg?

What graphics library is configured? These lists come straight from that library. So we can only suppose the library is not configured to process them.

In that case contact your host.