Relative newbie here.
My slides have 4x3 aspect ratio, so exporting the slideshow at 1920 wide, the height should be 1440. However, when I try to set 1920x1440 as a custom resolution, PhotoStage says "Please enter a height that is no more than 1080."
As PhotoStage export other aspect ratios with more than 1080 in height, this limitation seems arbitrary.
Of course I can use 2560x1440 but this puts wide black bars on the sides.
Of course, it's possible I'm missing some basic insight here.