Heh, that will also show up any dodgy pictures from your temp internet folder! So be careful who is looking over your shoulder
If you have for some obscure reason saved your pictures as bitmaps you can save a lot of space by saving them as jpg. although its a lossy format it is accepted as teh de facto standard for pictures nowadays. If you really want to keep them as uncompressed, then TIFF is the format to use(Bitmaps ncan easily be corrupted)