that's because paint has crappy resize - you can't specify the dimensions, you can only make it as a percentage of the original picture.
anyway, as i said originally, photoshop is the best thing for this particular job, but mspaint is good for printscreen jobs (printscreen, paste into paint, select the part you want, copy, new file, paste, save), which i do quite a bit. it's also good for games that don't have a screenshot key, just hit printscreen and paste into paint later. the jpeg quality is pretty much ideal for web-quality shots, as disposable images.
as for your comments on PNG, strider, you are wrong. PNG is best for images with lots of whitespace (or any other space of some single colour), making it ideal for screenshots of websites, plain text, and the like. transparency is a useful addition, yes, but PNG is not by any way limited to small graphics. large images with lots of whitespace compress far better as PNG then JPEG. in addition, PNG compression is lossless, which furthers it's usefulness with screenshots of plain text and websites. (although it is not limited to these uses)