Most photo software that comes with computers or cameras has options that allow you to resize pics and let you choose what quality or resolution to save it at. I usually take big high resolution pics and save a resized, lower-res version for posting. If your photo software has a crop feature, you can resize your pic, then crop out a lot of background clutter to cut down on file size, also. Most pics have a lot of empty space around the subject that is just taking up kilobytes.