Sometimes words just won't suffice to find an image. When you're having trouble finding that perfect picture, don't change the search terms—draw it instead with the Splash search engine from 500px.
The experimental tool from the stock photo service lets users sketch out an image using a digital drawing pad. Swap the size of the paintbrush and the colors you draw with and do your best to doodle out the image that you'd like to find. From there, the Splash searches from the database of images collected by 500px to find the best match available. The tool also lets users set a category—like landscapes or animals—to better direct the results. The tool is still in its very earliest iteration, so the functionality is limited—as are the search results, since the tool only sources from the 500px marketplace. But you might be surprised at just what your drawing manages to yield.
Play around with the tool and see what you can find. You might be surprised at the interpretations the tool comes up with for a couple simple brush strokes.