Did you enable users to post with HTML? Are they uploading the images and then attaching them into their posts? Is that how they are still posting images?
No HTML. Users could post images just using img bbcode. But after I put if($allowimgcode !="no") in the file, it's fixed. If you look in upload/inc/functions_post.php, you'll see stuff like
if($allowmycode != "no")
if($allowhtml != "yes")
if($allowsmilies != "no")
So I just changed if($allowimgcode) to if($allowimgcode !="no") so it looks like the others. Now it works.