There are 5 formats in this gallery. Backgrounds are grouped by format. If your phone has a 5:3 Aspect Ratio and is not an Android, such as the win7 Phone, use the Win7 Phone Backgrounds. If your phone has a 2:3 Aspect Ratio and is not an Android, like the Iphone, use the Iphone Backgrounds. If your phone has a 5:3 Aspect Ratio and is an Android, use the Android 960x800 Backgrounds. If your phone has a 2:3 Aspect Ratio and is an Android, use the Android 640x480 Backgrounds. If your phone has a 9:16 Aspect Ratio use the 9x16 Backgrounds. I have tried to provide the highest resolution of each aspect ratio that I am aware of exists on phones, therefore, if you have a smaller resolution, you may have to manually downsample it in an image program if you phone won't do this for you automatically. If none of these fit your phone, leave a comment and I'll try to make something work.