You can't show a bigger picture, because that's as big a picture as you have in your Photobucket album. If you still have the original sized picture in your computer files .... upload it again, into your Photobucket album, but this time choose the resize option of "Large" 640x480 pixels. This will give you the largest size picture that should be used on this site.

I'm assuming, of course, that you used a digital camera (or film camera & scanner) to get your pics loaded into your computer, then uploaded them into Photobucket. You can get good quality small pics, from larger pics, by downsizing ... but, if the original picture is small, and you try and upsize them, they'll come out pixelated (fuzzy, grainy, blurry, etc)

... cp