There are quite a few nifty commands that you can use with google’s amazing search engine. One that I use quite often is the imagesize command.
Say you want to find a new desktop background for your computer. It you’re like me you don’t want the picture to be all stretched and poor quality in order to fill the screen. In google image search you can you the command imagesize:followed by the dimensions you want to use.
For example my monitor’s resolution is1680x1050, so I would use imagesize:1680×1050. Remember no spaces! This only gives resulting images of that resolution. So if i google background imagesize:1680×1050 then i get a load of background of the right resolution.