Quote Originally Posted by SadieKate
But what do you do if Photoshop smarter than you are?
I use Adobe Photoshop Elements - it's much more reasonably priced than the full photoshop product although I'm sure it's missing the more "professional" features. It has what I need though. I suspect other tools have similar features.

To create an avatar, I open the picture I want to use. Then I request Save for web. That brings up a window that shows me the photo and lets me specify a size in pixels. Since the TE guidelines - stated on the User CP Edit Avatar page - are "100 pixels by 100 pixels or 9.8 kb, whichever is smaller", I just started with adjusting the width or height (whichever was longer) to 100. That created my little picture.

If you don't have a tool like photoshop, I'd go along with LBTC's recommendation of using the free tool IrfanView.