2D iphone / ipad resolution?

Hi there

Apologies for the noob question… I am new to game development and Unity. I’m creating a 2D game that I’d like to publish to the iPad and iPhone.

My question is, what size do I need to create my background graphics / smaller assets in order for them to look really crisp on both devices? I have looked around for this question but I can’t find a suitable answer.

I have it in my mind that I will need to create two sets of art assets one size for iPad and one for iPhone. If this is the case what size do these need to be?

Again sorry for the stupid question.

Standard iPad resolution: 1024x768 (2048x1536 for retina display)

Standard iPhone resolution: 320×480 (640×960 for retina display)

iPhone 5: 640×1136

You should work with the largest size you plan on supporting and scaling them down appropriately when chopping them up for programming.