How do you lower a picture's KB size?

There are 3 way this could be done. 1. If you only need a certain area of the picture you can use the crop feature and cut out areas of the picture you do not need. 2. Try saving it as a different format to to "Save As" and try saving it as a .tiff., .bmp, jpeg,... or something else 3. Or before you save in under save preferences there is usually a image quality selector you can select from High to Low try saving it as a lower quality.