I think a big part of the problem lies in unrealistic expectations, as a result of
the way people post advice and solutions. Time after time, I've seen posts saying something on the order of: If you use SVG wrapper,
the image will fill the screen.
I know they *mean*
the longest dimension will fill the screen, and the shorter dimension will not (leaving a white border at its edges), if the aspect ratio of the image does not exactly match the device screen. But that little detail is seldom mentioned, so novice bookmakers are almost sure to be confused when their spanky new cover does not "fill the screen".
EDIT TO ADD:
PS: An interesting explanation of svg wrappers and aspect ratio was shown by RbnJrg on thread
https://www.mobileread.com/forums/sho...=215088&page=2, by using the svg wrapper attribute "slice"; added to the wiki. It may be a solution *sometimes*.