Sorry if the question title is confusing, but if I knew how to say ot correctly, I would've googled my question :D So I am having difficulties understanding how to create different assets for different screen sizes, for example I have a working file in Photoshop of a button which is 550x550 pixels, and I want to have something like an universal formula to calculate how to make different image sizes for the different screens. Also, it would help if there is some quick function in Photoshop for creating them
I often use this site to calculate quickly the various sizes for density:
http://labs.rampinteractive.co.uk/android_dp_px_calculator/
Also Cut&Slice allows you to create the different assets with Photoshop CS6