Does DPI Matter?
Here’s a side-by-side comparison of the image as it appears at all three of the above resolutions. I’ve made the image smaller (it’s now only 200 x 200 pixels) so I can fit all three versions next to each other, but the first version on the left was saved at 72 dpi. The version in the middle was saved at 240 dpi, and the version on the right was saved at 500 dpi:
As we can clearly see, the resolution has no effect at all on how the image looks on screen. All three versions each take up a space of exactly 200 x 200 pixels regardless of the resolution setting. The quality of each version is also exactly the same. Each version would print at a very different size because of the different resolution settings, but it makes no difference whatsoever to the screen size or to the image quality.
While it’s doubtful that this 72 dpi web and screen resolution nonsense will go away any time soon, I hope this tutorial has at least made it easier to see why it is, in fact, nonsense at this point. Computer monitors these days all have screen resolutions higher than 72 dpi , and the image resolution option in Photoshop affects only a photo’s print size, not its screen size or quality.
Any photo with pixel dimensions small enough to display on the web would be too small for anyone to download and print a good quality version at a useful size, so with all these reasons in mind, if your photo will only be viewed on screen, whether it’s on the web, in an email, or whatever the case may be, there is simply no logical reason why you would need to set its resolution to 72 dpi in Photoshop. Unless you’re printing the photo, you don’t need to worry about image resolution at all. And there we have it!