Explain the difference between drawable, drawable-ldpi, drawable-mdpi and drawable-hdpi

Question

I have a rough idea of what each of these directories are for, but I\'m not really clear on the concept and I have some specific questions.

For example, what are the

Answer 1

Due to different screen size and resolutions, Android lets you arrange your drawable images according to folders. Images for high dpi displays should be placed in hdpi and similarly mdpi and ldpi. The default folder for the drawables is drawables if the operating system does not match any dpi category or the resources is not found in special dpi directories the system picks the resource from the drawables directory.

The size are not exact but upto 130dpi it is considered small, from 130 to 180 it can be considered mdpi, from 180 to 200 it can be considered as hdpi and the higher is classified as xdpi.

http://developer.android.com/guide/practices/screens_support.html