Q for people who publish to desktops/laptops -re sprite size

Just a quick question, what's the largest single-sized sprite you've used your games?

1600x900 but I configured it to be an optional download rather than embed the hi-res image in the game.

probably not the most efficient use of memory but for the moment it works.

Keep 'em as small as possibile.

Do I need to make the sprite pixel size same as the screen size to be able to show the sprite covering the whole screen clearly?

Just make image size of the screen, and cut then in to smaller power of two size sprites ( 64x64px or 128x128px, 256x256px etc ).