android - background image size for mobile devices -

I want to show a background image in my Android application.
What is the ideal image size (width and height) for all mobile to fit in screen resolution?

The id says that it will be ideal to use the highest screen density so that the app is for less screen Scale the way you get used to loose quality on large screens, I turn off that chart from here

  xlarge screen at least 960dp x 720dp big screen at least 640dp x 480dp normal screen is at least 640dp x 480dp 470dp x 320dp Small screen is less than 426dp x 320dp for screen Valid DPI value: ldpi low density (Eldeepiai) screens (~ 120dpi) processing medium density (Mdeepiai) Resources for screens (~ 160dpi) for. (This is baseline density.) Resources for HDPI High Density (HDPI) screen (~ 240 dpi). Xhdpi resource for the extra high density (xhdpi) screen (~ 320dpi) therefore the normalized size of your resources (assuming they are full screen): LDPi Vertical = 426 * 120/160 = 319.5px Horizontal = 320 * 120/160 = 240 pixel MDPi Vertical = 470 * 160/160 = 470px horizontal = 320 * 160/160 = 320px HDPE Vertical = 640 * 240/160 = 960px horizontal = 480 * 240/160 = 720px xhdpi workspace = 960 * 320/160 = 1920px horizontal = 720 * 320/160 = 1440 px px = dp * dpi / 160