image for joystick by percentage of screen?

Questions & Answers
1

hi guys how i can scale ui image by percentage of device screen?

2

Making an image expand to % of screensize:

  1. Menu: GameObject → UI → Image
  2. Set: Rect Transform - Anchor Preset (click on the image) - Stretch/Stretch
  3. Set: Left/Top/Right/Bottom - all to 0
  4. Set: Scale - whatever you like in percent [0…1]
  5. Set: Image - Source Image - to your image
  6. Read docu for more awesome

Loading different resolution of the same image depending on device:

This can be done using AssetBundle Variants. Find more about it on the AssetsBundle tutorial page (search for USING ASSETBUNDLE VARIANTS)