Trouble getting pic filesize within upload limit

While making multiple Paint.net files with two pics each (~1.25 MB) and then using the originals as templates, I noticed to my disappointment that the last few I made bloated up to ~3 MB each and were too big to upload to UT. I made them again, erasing the pics on the templates and making double sure the replacement pics were .jpegs, not PNGs, but the filesize didn't shrink at all.

WHAT HAPPENED?

if you upload them via photobucket or something like that, you won't need to shrink them down at all....