Android icons require five separate sizes for different screen pixel densities. Icons for lower resolution are created automatically from the baseline.
mdpi (Baseline): 160 dpi 1×
hdpi: 240 dpi 1.5×
xhdpi: 320 dpi 2×
xxhdpi: 480 dpi 3×
xxxhdpi: 640 dpi 4×
Three-dimensional, front view, with a slight perspective as if viewed from above, so that users perceive some depth.
48 × 48 (mdpi)
72 × 72 (hdpi)
96 × 96 (xhdpi)
144 × 144 (xxhdpi)
192 × 192 (xxxhdpi)
512 × 512 (Google Play store)
These icons are used in the action bar menu. The first number is the size of the icon area, and the second is file size.
24 × 24 area in 32 × 32 (mdpi)
36 × 36 area in 48 × 48 (hdpi)
48 × 48 area in 64 × 64 (xhdpi)
72 × 72 area in 96 × 96 (xxhdpi)
96 × 96 area in 128 × 128 (xxxhdpi)
Small icons are used to surface actions and/or provide status for specific items. For example, in the Gmail app, each message has a star icon that marks the message as important.
16 × 16 (mdpi)
24 × 24 (hdpi)
32 × 32 (xhdpi)
48 × 48 (xxhdpi)
64 × 64 (xxxhdpi)
These are used to represent application notifications in the status bar. They should be flat (no gradients), white and face-on perspective.
22 × 22 area in 24 × 24 (mdpi)
33 × 33 area in 36 × 36 (hdpi)
44 × 44 area in 48 × 48 (xhdpi)
66 × 66 area in 72 × 72 (xxhdpi)
88 × 88 area in 96 × 96 (xxxhdpi)