As you know, you can't put a picture on a sticky, so this is the next best thing. Combine the decades old concept of ASCII art with a text-only sticky, and you can put an image on a Sticky! By using a fixed-width font, and letters arranged in the order of how dark they are when shown in that font, you can take a jpg, and write a sticky with an image on it.
You can see the app running to the right. Click on the picture for a better look at it, and then download it from the Link below. Please bear in mind that this is not going to put a beautiful picture of your favourite girl/car/gun on your desktop, but it will put a hacked up, jagged, black and white version of that image on your desktop. It's not big, it's not clever, but I bet you can have some fun sending amusing images on Stickies across the network to your colleagues ;)