you can do it with paint too...just when ur saving it, type in the file type that you want it like 'ski.jpg' or 'ski.gif' but it messes it up sometimes so photoshop's the best thing to use for that especially if you want to make the file size smaller.
Skiing is not for the simple minded, that's why they invented the snowboard.
There are a million places you can get photoshop for free. The easiest one is prolly kazaa. Thats where i got it. When you get photoshop, go to SAVE FOR WEB, itll compress it good without effecting the dimensions