Retina graphics and file sizes
March 23, 2012
Retina-optimized graphics are awesome, we all pretty much agree. But there comes a trade-off with such: file-size. TUAW’s Mike Schramm summarizes the issue:
The most obvious drawback is app size. Those bigger graphics take up more space, and for many graphics-heavy applications, that could put them over the cellular data download limit (now at 50 MB). Universal apps specifically are taking this hit, even if they’re not running with the new iPad-sized graphics on the iPhone hardware.
A good universal app today supports four resolutions:
- Legacy graphics for the 2G iPhone, iPhone 3/3GS, and iPod Touch.
- Legacy graphics for the original iPad and iPad 2.
- Retina graphics for the iPhone 4/4S.
- Retina graphics for the new iPad.
There are ways to mitigate the file size increase, such as recycling retina iPhone graphics for use on older iPads. In search of real-life examples for how an app is distributed, however, Lex Friedman at MacWorld compared the pre-retina and post-retina file sizes of Apple’s own universal iOS apps. In doing so, we see file sizes roughly 2.75 times greater post-retina.
Between this, camera improvements, and more computing power to push more detailed textures in 3D games, there’s a reason the 16GB new iPad isn’t recommended by a lot of bloggers.1
While we can assume that support for older devices will drop in the future, we still have at least a generation or two to go before non-retina devices are no longer supported by new versions of iOS. And even when that time comes, dropping non-retina graphics files won’t drastically improve the footprint of app file sizes, since it’s the retina versions that are making file sizes much bigger. At the very least, we should expect next year’s iPad to offer a 128GB storage option.
In the meantime, we still maintain that better cloud tools would help immensely, especially with large iPhoto libraries that can take up considerable storage space. Another potential solution on Apple’s side is to somehow strip graphics from AppStore downloads that aren’t needed on a target device. For example, retina graphics would be removed from an app downloaded from a non-retina device, and iPad graphics would be stripped from a universal app if installed on an iPhone.
Then again, perhaps we’re making too large an issue out of one that’s easily rectified in one or two generations, as flash storage becomes cheaper. Still, it’s enough of a problem that some are pushing not to release universal apps in order to save on storage space, a proposal that we find to be a rather bittersweet solution.
We’d only recommend the 16GB version for those who primarily only surf the web and use a small number of apps. For the average user, 32GB sounds about right, while 64 GB is probably a little too much, and barely adequate for advanced users. ↩