When someone asks me for a ‘set of application icons to cover all platforms’ they are usually shocked by just how many different sizes and formats are required. In fact, this is something that seems to evolve and increase every few months.
There is some overlap across legacy platforms but most newer mobile platforms choose icon dimensions with frustratingly random dimensions. Even Apple requires both 57×57 and 58×58 pixels for iOS for application icon and spotlight icons respectively. What can possibly be gained from just one pixel? I wish I knew! Luckily, bar a couple of exceptions, the PNG image format rules all platforms.
For those who need to know, here are the icon sizes you will need if you want to produce application icons to cover all the main platforms. Please note this guide is a ‘catch-all’ designed to cover every icon size you are likely to need. In practice not every size listed here will be needed. But I like to have all things covered rather than the client come back to me a week after the project is complete, asking for more sizes.
All the image sizes need to be combined into an ICNS ‘container’ and technically 8bit and 4bit versions of each size must also be included, although in reality these are rarely if ever displayed. Most would probably choose to omit these for the sake of time and file size.
Windows 7 & 8 Icons
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As with OSX, Windows icons must be rendered into a single file, in this case ICO. Multiple colour bit depths are also recommended, 24bit, 8bit, 4bit and even mono icons. Although like for OSX I have rarely seen an actual time any of these are used. The only exception is 8bit which some older software development requires to display correctly.
Windows Phone 8 Icons
- 99×99 Application Icon
- 70×110 Small Icon Tile
- 130×202 Icon Tile
Windows Phone 8 icons are probably amongst the most complicated in terms of the rules on sizes, padding and display. A more in depth guide can be found in a previous article Windows Phone 8 Icon Size Guide
Android icon sizes seem the least intimidating with just 4 sizes in use across devices and the 512 size used within the Android App Store. Thank you Android!
Apple, as usual, like to do their own thing and rather annoyingly keep changing their minds and adding new sizes, iOS7 being a prime example. It is OK though. We really have nothing better to do that optimise and render off another size you may or may not decide to display!
Remember that Apple icons need a filled square background so you can’t just re-use other icons made in the same size from another platform.
Anyone keeping count will know that is 32 icon sizes! If you are happy with a consistent style cross platform then luckily some of those can be shared but that still leaves us with 27 unique icon files/sizes to render to cover all popular platforms.
The next time someone asks why it costs so much to create a set of App icons, point them here. 🙂