The following list shows the sizes needed for the graphics.


Short list of needed assets used for most devices:


iOS
Android
iPhone (at least 640 x 960 px)
Portrait (at least 1600 x 2560 px)
iPhone 5 (at least 640 x 1136 px)
Landscape (at least 2560 x 1600 px)
iPhone 6 (at least 750 x 1334 px)

iPhone 6 Plus Portrait (at least 1242 x 2208 px)

iPhone 6 Plus Landscape (at least 2208 x 1242 px)
iPad Portrait (at least 1536 x 2048 px)

iPad Landscape (at least 2048 x 1536 px)


Note:  Please make sure that the aspect ratio of the pictures are the same as suggested above. 

Extended list for more display sizes and aspect ratios:


iOS
Android
iPhone (320x480) Portrait (320x512)
iPhone (640 x 960) Portrait (640 x 1024)
iPhone 5 (640 x 1136) Portrait (800 x 1280)
iPhone 6 (750x1334) Portrait (960x1536)
iPhone 6 Plus Portrait (1242x2208) Portrait (1600x2560)
iPhone 6 Plus Landscape (2208x1242) Landscape (512x320)
iPad Portrait (768 x 1024) Landscape (1024x640)
iPad Landscape (1024x768) Landscape (1280x800)
iPad Portrait Retina (1536 x 2048) Landscape (1536x960)
iPad Landscape Retina (2048 x 1536) Landscape (2560x1600)