Does your 3392 pixel image have mip maps? If not, then trying to render that image into a screen that is only 660 pixels wide is going to cause a lot of trouble for the texture caches on your GPU since every texture fetch is going to be looking up texels very far away from the texels requried for neighboring pixels. Having mipmaps for your giant background texture will mitigate this problem as the GPU will use a lower resolution mip and texel fetches will be much more local. But this raises the obvious question: why are you using a 3392 pixel background when your screen is only 660 pixels? The memory requirements are much higher, and with mip mapping the higher mips will never be used, so it is just wasted memory.
Ah I see. Larger image means larger memory usage. Thanks for the information!
The image is not using mip maps.
That is a pretty cool technique though now that I think about it...Calculating beforehand for optimal performance. I will research more about this and apply it to my game! Thanks!