I got this e-mail from a friend!
How do I edit my own picture so it is formatted to the correct size to be used as a wallpaper on my iPhone 4?
I wanted to tell him to use Google, but instead I decided to write this quick blog post. Let’s see first what Apple has to say about the iPhone 4 screen to get an overview:
- Retina display
- 3.5-inch (diagonal) widescreen Multi-Touch display
- 960-by-640-pixel resolution at 326 ppi
- 800:1 contrast ratio (typical)
- 500 cd/m2 max brightness (typical)
The iPhone 4 and the iPhone 3Gs have completely different pixel resolution. The iPhone 3GS has a resolution of 480×320 pixel and iPhone 4 has a pixel resolution of 960×640. The answer is to use your favorite software to crop your image to 640 X 960 and you should get a reasonable enough looking custom wallpaper!
If you are looking for a free editing tool give Gimp (windows) a try. I edited the above promotion picture for the TV show The Big Bang Theory to the correct size as an example – for the iPhone 4. Try it on your iPhone and let me know what you think!


I realize this is from September 2011. But I came across this via a Google search. And want to post this here.
Some people are interested in knowing the screen size in pixels. As opposed to inches, which seems to be the only information to be found. And even then if we knew the length and width, instead of the diagonal size that would be helpful.
Some would rather size their picture to the actual size of the screen instead of trying to take advantage of the high resolution.
I would not blame you for the exclusion of this information, since it seems as though I cant find it anywhere else either.