On the developer's console when you go to publish your android application the screenshots are needed with the following specifications, 320 x 480, 480 x 800, 480 x 854,1280 x 720, 1280 x 800 24 bit PNG or JPEG (no alpha) Full bleed, no border in art. Now on this link it says, "You may upload up to 8 screenshots." My questions is,
https://support.google.com/googleplay/android-developer/answer/1078870?hl=en&ref_topic=2897459