What exactly do you ask for from your graphical designer for your iphone apps?
I asked my designer exact measurements of images in Photoshop, which turned out to be not such great idea because I need to ask for new images to support the new iphone 5, and if I want add ad-support I'd need new images as well.
What do you ask from your graphical designer to avoid these common scenarios?
I talked with my graphical designer and she said that it's possible to make high resolution images - higher than let's say bigger than iphone's 5 resolution, which is 1136x640. Then I could scale down the images size using Photoshop/GIMP as needed.
Another solution was to create the image in Illustrator, which from what I could understand, one can always change the resolution without altering image quality.