Everybody who has an iPhone or a 3G-capable iPad knows the frustration: you’re out somewhere and you hear about an app you want. You go to the App Store, find the app, and start the download. You put in your password and wait for your app to start downloading. Only then do you see it: the message telling you the app is too big to be downloaded over 3G. You have to either connect to a wi-fi network or get it from iTunes on your computer.

Now it looks like that problem might be getting worse soon. The iPad 3, which is set to launch next week, is all but certain to get a retina display like the one in the iPhone 4S. While that’s definitely great news for the overall iPad 3 experience, it may not be so great for downloading an app over 3G. You see, to get retina display graphics on an iPad, app makers have to vastly increase the pixel size of their images. At the same time, to make sure the apps display properly on older iPads, they have to include the lower-resolution images too. The extra (large) images mean bigger file sizes for the apps. That, in turn, means that many apps – especially those that were close to the limit already – are probably about to break that 20MB threshold.

Now, this certainly won’t impact all iPad owners. Many of them, after all, go for the wi-fi only model. For those users, whether the apps go over 20MB won’t make much of a difference. Of course, the issue can also affect iPhone owners. Many apps are universal – they run on both the iPad and the iPhone. In fact, those apps are often the ones closest to the 20MB threshold, since they have to include two complete sets of graphics for the devices they support. Adding graphics compatible with the iPad 3 retina display to those apps could well push them over the limit, causing headaches for iPhone owners, whether they own an iPad or not.

All in all, the problem isn’t likely to be a huge one. Wifi networks are growing more and more common. But it could be pretty annoying to a lot of users.

What do you think? Should Apple relax the 20MB download limit to make life easier for iPhone and iPad 3 owners? Have you ever run into problems with the download limit? Let us know in the comments.

[Hat tip, The Next Web]