Originally posted by: kamper
It's not that hard in Paint. You grab the resizer at the lower right hand corner and drag it left or right, up or down until you're at 100 pixels. (That is, if you don't mind chopping or adding whitespace). If you want to resize the actual contents: Image -> Stretch/Skew, but that will probably make it look not-so-nice.
I don't have Photoshop. I do have (I think) Photoshop Lite, or something like that. I'd have to look for it. I do have a copy of CorelDraw (Full version) from around 10 years ago and I guess it came on 1.4 MB floppies!

Wouldn't be surprised it it would work for this, but don't know that I want to bother to find out.
In Paint, resizing by dragging the corner just gives me the top left corner of the picture, maybe I'm doing something wrong. Stretch/Skew does the job but I have to guess at the correct percentages. 8% is very close - it gives me 103 x 77 pixels. It's not quite down to 100 x 100 pixels. I'll see if the site complains. Thanks!
Well, it didn't like it so I reduced vertical and horizontal dimentions using the factor .97 and it turned out 100 x 75 pixels, and it's accepted.