I have an app that creates for android and ios uses 4 different images can't decide the right size for each of them It is the full screen image minus almost 200 px. It is a background image for button ( image descripe what button do ) and take us to No 1 to display the full screen image under the background image of button Third one is an image take full with of screen and 1/3 height of screen We have a note page that use have only text input but should display lines in background ( as u typing in lines ) text have lineHeight 26 px. This images will be dynamic client will add from backend

Ideal size of images for mobile app android and ios

I have an app that creates for android and ios uses 4 different images can't decide the right size for each of them

It is the full screen image minus almost 200 px.
It is a background image for button ( image descripe what button do ) and take us to No 1 to display the full screen image under the background image of button
Third one is an image take full with of screen and 1/3 height of screen
We have a note page that use have only text input but should display lines in background ( as u typing in lines ) text have lineHeight 26 px.

This images will be dynamic client will add from backend