Francesco Vezzoli, Portrait of Lady Gaga
Artist Francesco Vezzoli combines the art of film and the art of embroidery to create his work. His best know pieces are these serigraphs in which details of the images are hand-stitched using petit-point embroidery techniques in shocking colours. There's an interesting interview with him over on FlashArt Online, here.
Petit-Point is a needlepoint stitch similar cross-stitch but it's worked on canvas and is even smaller in scale. If your thinking about embroidering onto images it's important to think about what you will stitch into - photographs? fabric? etc and what embroidery techniques you might use; there's lots of them! This post on Craftster is a great starting point to explore different techniques and Mr X Stitch is a great resource for inspiration!