I set up a design contest, and for some reason, it is not letting people display more than one picture per post.

I can't provide more information without seeing the post.

But if I had to guess, there's an error in your post code that's breaking the rest of the images. Make sure all the brackets are complete and that you are using the appropriate tags in the appropriate way.

There also is a known issue of using the same destination URL with different text. You can bypass this error by slightly changing the links so that they are unique. Example:

[ url=www.sylestia.com]Link 1[ /url]
[ url=www.sylestia.com]Link 2[ /url]

The above would not work. Both are linking to the same destination URL but using different text (Link 1 and Link 2). You can fix this by doing:

[ url=www.sylestia.com#1]Link 1[ /url]
[ url=www.sylestia.com#2]Link 2[ /url]

Cool, thanks, I will add that
also, heres the link to the contest:
https://www.sylestia.com/forums/?thread=70439

Which post are you having issues with?

Um...I mean like when a person posts a reply, they can only use one image a post

There would be no reason for that outside of what I originally said. If they are having issues posting, they will have to let me know what specific issues they are having.