If you are using your computer, them you should be able to right click on the photo and a drop down menu with "properties" will appear. If you click that, it should show the pixel width and height. If you are using your mobile phone, I am not totally sure how to check, but if you go into camera settings you may find the what resolution your camera is. If your camera is 7 megapixels (MP) or higher you should be fine. A lot of current cell phones have a camera that takes photos with that resolution now. If you have an even higher MP resolution, you could crop your photo and still have high enough resolution.I'd like to post a pic for submission but how do I know what my resolution is?