Can't add pictures to my game?

EOTW

Hi, i'm making a game called Ice Cream Clicker and i'm trying to add pictures to upgrades, achievements, and the background. I've already looked to see what the problem was but came up with nothing. Can anyone help me? Thanks.

DtjiPsimfans

The background images cannot be too large or too small. If they are either too large or too small, they can't come up in your game.

EOTW

I already fixed it. Thanks anyway though!