Welcome to MadModder!
There are many occasions when folk have posted about resizing images.....If you go to the Windows website and download the image resizing tool it will assist in resolving in this issue.....http://windows.microsoft.com/en-GB/windows/xp-downloads#2TC=powertoys
Ms paint stretch is about the clumsiest tool you could imagine for re-sizing, and the file sizes aren't great either....