Don't Zip jpg's, it's a waste of time. If there's more than 5 or 10 MB's of data to transfer, get yourself a free account on dropbox.com, put your images in there and give permission for others to read and write files to that folder. You'll need the email addresses of the people you want to access the dropbox folder.
And I still recommend GIMP for picture processing. I've been using it pretty steadily for the past week or so, and I haven't run into any limitations on the things I've wanted to do.