I was reading this to understand sprites
The author says "Sprites are for graphics that are just single blocks. " What does this mean? One thing I have read is to make a sprite for images which are continuous on a web page.
It means they cannot be used as a pattern. Take a look at the small print under that paragraph:
So, sprites should be used for graphics that are only displayed once (such as an icon). They should not be used for a gradient pattern intended to be repeated vertically or horizontally and especially should not be used for a tile-able background