Hey everyone,
so my current project is that of an E-Book. My main concern before i get started with the graphics, is deciding what size to create the originals in photoshop, i prefer this rather than doing vector. I want to release the e-book for both ios and android devices. So I am trying to decide what resolution to create the originals at. One main concern is that ios devices seem to have a 4:3 aspect ratio, and Android has the 16:9 (widescreen). Just wondering if anyone has any thoughts, opinions, or experience with what is the best way to handle this ( seeing as these are graphics that fill the entire screen )
I would like to make them plenty big so i can always scale them down, im thinking of maybe doing 2560 x 1600? what are your thoughts? thank you

Actually, iPhones and iPod touches are 3:2 ratio, the same as a 4x6 photo. iPads are 1024x768 which is a typical standard def TV/Computer monitor 4:3 ratio. Most android phones are 16:9 high def TV format.

But Android tablets are another story. Common screen sizes include:

1280x800 (8:5 ratio)
1024x600 (5.12:3 ratio)

If you build for 16:9, you're going to letterbox on iPhones some and iPad's alot.

If you build for iPhones you're going to letterbox some on iPads and either crop on the 16:9 devices or have the black letterbox boxes on the sides instead of the top (assuming landscape)

Build for 3:2 which will letterbox a bit on the iPads, be full frame on the iPhones and leave enough at the top and bottom that the 16:9 devices can crop. The 8:5 tablets will crop a little

For example, all my graphic in 4000x2500 resolution and I have no problems. All my games was designed with virtual background expanding possibilities (and therefore I have no problems with display ratio)

great thanks for your ideas and input, im going to keep researching it and post back with my final decision