[Dabcar]

What's the best format for images in Kindle devices? My images at present are in transparent PNGs, but that produces black backgrounds within Kindle Previewer, so I'm guessing that Kindle doesn't like transparency.

Also, what sizes are recommended. I see in the Amazon Kindle guide very large sizes for modern devices, but what's the best rule of thumb?

Is there any difference for epub devices (not Kindle)?

I have tried to search for answers to this in the threads, but can't come up with anything, so I'm sorry if I'm repeating or not looking in the right place!