hdpi ldpi mdpi icon/menu resolution
Everything you need to know is here in the official documentation.
Launcher icons
48 × 48 (mdpi)
72 × 72 (hdpi)
96 × 96 (xhdpi)
144 × 144 (xxhdpi)
192 × 192 (xxxhdpi)
512 × 512 (Google Play store).png
Action bar, Dialog & Tab icons
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)
.png 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.
Notification icons
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)
.png These are used to represent application notifications in the status bar. They should be flat (no gradients), white and face-on perspective
Small Contextual Icons
16 × 16 (mdpi)
24 × 24 (hdpi)
32 × 32 (xhdpi)
48 × 48 (xxhdpi)
64 × 64 (xxxhdpi)
.png 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.
For more information, use the android developers iconography material.
http://developer.android.com/design/style/iconography.html
This Link is Help you To set Images for Your Application
http://developer.android.com/guide/practices/ui_guidelines/icon_design.html
Other than Below Link is also may help You....
http://developer.android.com/guide/practices/ui_guidelines/widget_design.html