Udacity - Basic nanodegree -Make Your Own Card (Lesson 4 Condolences) Part 2
Talks about Pixels, Dots Per Inch (DPI), How to calculate DPI, How to create different images size for different screens size on android studio
Greater resources to learn more:
Category of your image in dots per inch:
https://blog.mindorks.com/understandi...
Create different images based on screen size:
http://nikitadev.com/developer-tools/...
Understanding the difference pixel and dots per inch:
https://www.iprintfromhome.com/mso/Un...
Digital Ruler:
https://www.piliapp.com/actual-size/i...