If you use Outlook Express for email, it's a simple matter to shrink them. Find the pic, right click, send to, mail recipient, make my pictures smaller, then email them to yourself. Outlook will automatically shrink them to 640x480 for you.
If that doesn't help, open them in MS Paint (included in all Windows versions) and go to Image, then stretch/skew, then type in a percentage in each box (you'll have to experiment a bit to get the right size) then save as and give it a new name.
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