Ah yes by the way:
I remember someone on this thread lamenting the fact they couldn't upload files of a certain file size because they were too large/wide.
If you want to post them without resizing them, just put them under a spoiler. Apparently, the way thumbnails are made is dependent on the original filesize, if it's larger than a set amount it just crashes and won't let you post. Spoilering the file though solves the issue, since no thumbnail is saved.