There's also no reason you can't split the image up (e.g. 2048x2048 -> 4x1024x1024) and render it in 4 pieces. Where a hard limitation like that exists, implementations frequently sidestep them.

If you do this though, make sure you split at JPEG block boundaries. That means that every column should have a width divisible by 8 except the rightmost, and every row should have a height divisible by 8 except the bottom. Otherwise you may see a noticeable seam.

You can split the JPEGs at bit mapped images on the device before rendering. At that pointed you wouldn't be limited tithe block boundaries anymore.

edit for clarity: don't manipulate images in the JPEG domain.

Better make that 16 unless your image is greyscale.

I think it's actually just been doubled to 2048x2048. OpenGL ES 2.0 seems to define a 64x64 as the minimum requirement for texture size to meet the spec, which is really not much at all.