Check the following table and according to your image type, select the suggested dimension for your device.

 Image Type

 iPhone 4/4S

Android and iPhone5

 iPhone6 onwards

 Tablet

 Banner Ads

 640x100px

 640x100px

 640x100px

 1536x100px

 Bottom Navigation Bar (ex: Web Site Tab)

 640x88px

640x88px 

 750x88px

 1536x88px

 Bottom Tab Bar (Food Ordering/Real Estate)

 640x98px

640x98px 

 750x98px

 1536x98px

 Bottom & Top Tab Bars 

 640x88px

 640x88px

 750x88px

 1536x88px

 Contact Tab (Left/Right)

 288x144px

 288x144px

 288x144px

 288x144px

 Home Screen Buttons (Call Us/Directions/Tell Friend)

 190x60px

 190x60px

 190x60px

 434x76px

 Home Screen Tab Height (Top or Bottom Layout)

 130px

 130px

 130px

 260px

 Home Screen Tab Width (Left or Right Layout)

 160px

 160px

 160px

320px

 Home Screen Tab Icons

 75x75px

 75x75px

 75x75px

 134x134px

Home Screen Background Images

640x960px

640x1136px

750x1334px

1536x2048px

 More Menu Tab Icons

 70x70px

 70x70px

 70x70px

 70x70px

 Navigation Bar/Global Header 

 640x128px

 640x128px

 750x128px

 1536x128px

 Splash Loading Screen

 640x960px

 640x1136px

 750x1334px

 1536x2048px

 Status Bar

 640x40px

 640x40px

 750x40px

 1536x40px

 Subtab Icons

 105x105px

 128x128px

 128x128px

 256x256px