Can you make a image that's like 450 x 450 smaller? ...so it can be 100 x 100?

Sure, but it'll crop the image.
(I dunno about those other editing programs tho. I use MS Paint.)

Oh I use PSP 8 how do you do it on there?

yes, if you have photoshop go to the top where it say's image> image size> adjust it to your liking.

You could crop it a bit, and then resize the image to be 100x100.

Of course you can. lol
Just open up your 100x100 document and drag your other picture to it, then resize it by pressing "Control-T" and resize the image with the arrow thingy that show up..

That is, if you have PS7.

its basically the same for photoshop or psp probably..you might not even need to crop it because it's the same proportions. just find image resize/image size something like that and resize it 100x100