behind-the-scene technical aspect are not difficult to realize (either google image API, which is deprecated, or parse the result of http://www.google.com/search?tbm=isch&hl=en&source=h... and get the first image url after a predefined string anchor, say <span class=rg_ctlv>), but the idea to simplify input and output is brilliant.
To deal with not-so-good image search result: since google image search is presenting the result in a thumbnail group, it might be worthwhile to look into their ranking scheme for the result. It might be that the first one (on the top left) is not the most relevant result. It won't shock me if google ranked the relevance of result from center to peripheral. In the end that's how we look at a pile of images--we tend to start from the middle. Try a few examples, from the ones I tried the middle row middle column image is much more relevant than the top left result.
just my two cents.