Youp need to look at tiled image formats; you cannot just load an image of that size as a whole!
You have to find a way to load only sections of the image in memory to be able to display it.
Usually the image is split in tiles, each tile is a determined size (optimized for fast loading), and when you want to display the image in a region of the screen, you load the appropriate tiles corresponding to that section of the image.
I know TIFF offer that feature as well as other types of format; but you will need to do some work yourself.
Deep Zoom file format (msdn)