Is there a way to edit my pictures to fit exact dimensions?
Yes, there is a lot you can do with pictures. Judging by your question I don’t think you have any application you can use to help you with this… If you are using a PC (Mac is different) you should have MS Paint but is a pain to use and very limited. You can use Adobe Photoshop or any of their Photo editing applications but costs a pretty penny. Alternatively you can download an install an application called Gimp from www.gimp.org which is free and very similar in many of its functions to Photoshop. It has a few limitations but only comes in play when you are going into professional photography. In Gimp you can set the image size very easily to the exact dimentions you specify, in pixels, mm, inches etc.