Dick Move

I was puz­zled by this one too, but the only thing I can think of is that Apple may be using OpenGL to accel­er­ate the home screen. OpenGL on devices before the 3GS only sup­ported power-of-two sized tex­tures (128×128, 256×256, 512×512), while devices after and includ­ing the 3GS sup­ported arbi­trary sizes. This means that on the 3GS, they could imple­ment the back­ground using OpenGL with­out hav­ing to resort to load­ing an image into mem­ory that was larger than the actual screen size (power of two would require them to use a 512×512 tex­ture on the older devices).

The other pos­si­bil­ity is that they are try­ing to con­serve the already lim­ited amount of RAM on these devices — with­out the image, there is about 20-30MB of free RAM for 3^rd party apps. Having a back­ground image loaded all the time would require about a half a MB. Perhaps just this much extra usage was enough to cause prob­lems with some apps that expected to have more RAM avail­able.

I think this was a tough call for them to make — they end up upset­ting peo­ple either way, but in the end, it’s much bet­ter to lose the back­ground than it is for them to make apps that already work on the phone crash.