The following list and table show specifications and requirements for iOS screenshots for 4-inch Retina displays:
File Type: High-quality JPEG, TIFF, or PNG
Quality: 72 dpi, RGB, flattened
Transparency: Not allowed
Required: At least one screenshot is required if your app will run on 4-inch Retina displays and up to four additional screenshots are permitted
Type
Dimensions (px)
Notes
Portrait
640 x 1096
Do not include status bar
Portrait
640 x 1136
Fullscreen
Landscape
1136 x 600
Do not include status bar
Landscape
1136 x 640
Fullscreen