Update 09/18/2012 : changes in the new App Store (and new elements on the “Chomp” update) has given even more importance to your app screenshots, so we updated the post accordingly.
Along with your app description and your app ratings, your screenshots are what has to convince users to download or buy your app. In fact, I’d be tempted to say it’s the most important of the three (especially with the new App Store in iOS 6): if your app screenshots suck or if you don’t put the right ones, people won’t download your app. Like always, it doesn’t mean that great screenshots on your app store page will get your app massive downloads but it is required if you want any success with your app. Just like for your app icon.
A well designed app
You can’t have good screenshots without a good design. Obviously, a good design for your app is something you want to work on from the start. It includes a great user experience, simplicity and attention to details. It’s a topic way to important to be discussed in this post. Whether you’re a good designer, you hire one or you use app design templates you need to get that part right.
Use all available screenshots
Some developers don’t upload all the screenshots they are allowed to by Google and Apple (which is respectively 8 and 5 as I’m writing this) and that’s of course a mistake. Use as many as you can!
foot screenshot forward
Ok, maybe you designed a great splash screen but it doesn’t tell much about your app. The first screenshots that should be seen by potential users has reflect what your app is all about and why it is so great. This is even more true in the new App Store and its “Cards-like” UI: users see your first screenshot in the search results.
Test and improve
You can now only change your app screenshots when your app is an “editable” state. This makes it harder to test your screenshots whenever you want, but doesn’t mean you shouldn’t do your best to make sure they’re optimized. Test, analyze and improve.
Localize your screenshots
If your app is available in several languages, upload screenshots for each of them. It’s a pain in the ass to do (even if there’s an “easy” way to do it) but it is worth it if you’re serious about marketing your app somewhere else than in your country.
Add explanations to your screenshots
Don’t hesitate to write some explanations on your screenshots to make sure people that don’t know anything about your app can get it instantly. That’s something you don’t see that much (but I see this as a future trend) and that can be of great value to convince potential users to buy your app. Remember, they might read only a few lines of your app description!
Put four screenshots into one
I see that even less, although I’m pretty convinced it’s a good idea (I don’t have any numbers to confirm that, though). For iPhone screenshots, Apple requires 640×960 screenshots. That means that you can use 4 320×480 screenshots and make a 640×960 image for your app page. That combined with some writing can allow you to better explain user flow.
Want some great examples of do’s and don’t's? Check out this article.
Here are my tips for getting the most out of the screenshots of your app store page. If you want to keep up to date with the other aspects of App Store Optimization, check out our App Store Optimization page and our App Developer’s App Store Optimization Cheat Sheet.
Do you have any other thing in mind?