Determine what the best way to display images for both orientations are. Depending on how different things need to be, you got 3 basic options:
1) The difference are small, you just need to tweak positioning. This can usually be accomplished by adjusting the images struts and springers on the layout tab of at the nib editor.
2) You need to rearrange things to make more sense when rotated. In this case, implement willRotateToInterfaceOrientation and adjust the position of your images in this method. The changes will be animated automatically, so it usually already looks good even for simple adjustments.
3) You want to give the user a completely different experience in both orientations. In this case you might want to make separate view controllers for both orientations. There are quite a few tutorials to be found if you need this approach.
If its just a matter of placing the images in a way that they will fit, option 2 is probably the most suitable one.