According to my research from forums i got that main preview image size is ‘590x300’ and screen shot of pages ‘1920’ width and height as long as page goes but as i checked in requirements in the mentioned docs dimension seems different so please help clarify if the sizes are change now and also if any one can provide example documentation to follow. Thank You
https://help.author.envato.com/hc/en-us/articles/360000424863-Item-Presentation-Requirements .