what is the max size of the texture iphone can support?

Question

1024*1024? or only 2048*2048 in iPhone3gs and up?

Answer 1

As iPhone 3GS has PowerVR SGX535 GPU maximum texture size should be 2048x2048. For 3g limit is 1024x1024. You can find those limits in PLatform notes section of "OpenGL ES programming guide".