I have designed an image which will be used as a button in an android app. Since it is a button, the state of the image has to be changed when the user clicks on the image to give it a "pressed" effect.
How do you impart such an effect? Which tools should would be easy for this?
The easiest and simplest way would be to darken the button when its pressed. Applying a 30% black layer on top will do the trick.