I have never used GPUImage on iOS. Are we limited in resolution to the Metal/OpenGL ES texture size limit of a device with it? Can it work with extra large images?
Depends on your definition of extra large, I suppose. I've gone as big as about 10 megapixels in my implementations with it and it's held up.
The big problem with iOS image handling has always been the pitiful amount of RAM on the devices. It wasn't until relatively recently (iPad 4) that the iPads even had enough to reliably handle images in the 10-15 megapixel range without being killed by the memory watchdog.
Core Image on iOS is supposed to handling tiling of larger images automatically. This is one of the reasons I'm planning on porting my iOS video effects app from GPUImage to Core Image, although GPUImage has served me very well.
The big problem with iOS image handling has always been the pitiful amount of RAM on the devices. It wasn't until relatively recently (iPad 4) that the iPads even had enough to reliably handle images in the 10-15 megapixel range without being killed by the memory watchdog.