Images from my gallery are oversized and overlapping

Hello,

The images displayed within my posts through my inserted gallery are over sized (spilling over the margins), scattered, and nothing seems to help fix them.

I was using WordPress version 2.7 and recently upgraded to the the latest version of wordpress (2.8.4). I also moved to a better hosting account. In order to switch accounts I deleted all of my files and re uploaded the content. Does anyone have an idea on what the problem may be? THANKS!