Hi if anyone can help me to understand. I do not hv any screenshots in my uploaded file only one thumbnail of 590x300 but i got this reply… what exactly it means? 
Still please make sure your screenshot’s resolution is complying with the following standards, we’ve detected some incorrect resolutions. (Portrait: from 700px to 900px high, Landscape: min resolution of 1280 x 720 and aspect ratio of 16:9).