I think I fixed it. (I was able to upload 6 pics at once).

Actually I don't like the pic upload function. There's no preview and doesn't show the progress of each image upload.

I added the function that sorts the images before posting, so you can pick the main image and the order of the others under it.

I would like to rewrite the code of the entire site from scratch one day. (Hopefully would run a lot faster).