Actually, that was a problem I had with picasa.
When I use irfanview to edit, I grab the picture from the camera card, edit, resize, optimize for the web, and then save to the specific folder that I will be moving to a thumb drive and eventually use in my blog.
I leave all the pics on the camera card, saving to the computer only those pictures that are worth posting online.
I've never been able to figure out gimp...
I do have a freeware version of paint shop pro, but... Prefer irfanview.