forgot to add- I have been using my 5-year old, near-death MacBook Pro to complete these picture editing tasks on Premiere and haven't had any issues. This incident has occured over the course of three different project files, on two different external hard drives (one Thunderbolt, one firewire).
I use very few pictures, but these previous discussions may help... I'm not sure if these saved links are for PPro OR a Mac... but might help
Photo Scaling for Video http://forums.adobe.com/thread/450798
-Too Large May = Crash http://forums.adobe.com/thread/879967
-And another crash report http://forums.adobe.com/thread/973935
thanks john. Unfortunately, I don't think those discussions are related. This has happened to .tif images, .jpegs, and Mac screenshots.. of all different sizes. Some even under 1MB.