I would like to import a very large image into camera roll (or a folder in that directory) and I'm not sure of the best way to do it.

The images are Google Maps saved images which I want to use with the You R Here app. I want to try You R Here to avoid running up a huge data bill when I go travelling (don't want the phone constantly updating maps). I have looked at other offline GPS apps but they all save maps from other open source map providers (read inferior quality maps).

My phone is not jailbroken and runs firmware 4.2.

My questions:

1) Is there an upper limit to image size where the performance of the phone suffers or stops completely?

2) What software is recommended to import large images into the iPhone (I understand iTunes resizes the images such that it would be useless for this application)?

3) Can anyone suggest any other offline navigation apps ( I have OpenMaps, CityMaps2Go, MotionX GPS and You R Here(import images as maps), none of which have maps as good as Google Maps)?