IOS7 official recommended icons and image sizes

Icon and image size

Each application requires an application icon and a boot image. In addition, some applications require custom icons to represent application-specific content, functionality, or in the navigation bar, toolbars, and tab bar modes.

Unlike other custom artwork icons and images in your application, table 38-1 lists must meet certain criteria, so that iOS can be displayed correctly. In addition, some icons and image file naming requirements. (If you need an iphone or ipod touch device that supports standard resolutions, divide by 2 to list the high-resolution sizes below.) ）

table 38-1 custom icon and image size (pixels)

Describe	Size of IPhone 5 and ipod touch (High definition)	Size for iphone and ipod Touch (high resolution)	The size of the ipad is (high definition)	Size for ipad 2 and ipad mini (standard resolution)
Application icon (all required by the application)	120x120	120x120	152x152	76x76
For app Store (all app icons required by the app)	1024x1024	1024x1024	1024x1024	1024x1024
Launch Image ( required for all applications)	640x1136	640x960	1536x2048 (Portrait) 2048x1536 (Landscape)	768x1024 (Portrait) 1024x768 (Landscape)
Spotlight Search Results icon (recommended)	80x80	80x80	80x80	40x40
Set icon (recommended)	58x58	58x58	58x58	29x29
Toolbar and navigation bar icons (optional)	About 44X44	About 44X44	About 44X44	About 22x22
tab bar icon (optional)	Approx. 60x60 (max: 96x64)	Approx. 60x60 (max: 96x64)	Approx. 60x60 (max: 96x64)	Approx. 30x30 (max: 48x32)
The default newsstand is the App Store icon ( required by the Newsstand app)	The longest edge of at least 1024 pixels	The longest edge of at least 1024 pixels	The longest edge of at least 1024 pixels	The longest edge of at least 1024 pixels
Web Clip icons (recommended Web applications and websites)	120x120	120x120	144x144	72x72

All images and icons in PNG format are recommended. You should avoid using interlaced PNG images.

The standard bit depth for icons and images is 24 bits, and 8 bits are red, green, and Blue plus a 8-bit alpha channel.

You don't need to limit your web-safe color palette.