Google announced yesterday they have added support for Creator and Credit metadata and will be adding Copyright Notice metadata. This meta data will be used by Google to display Image Credits information on the image within Google Image Search.
Here is how those credit information items will appear in Google Image search on mobile after you click on an image:
Google added, "Also in partnership with CEPIC and IPTC, we hope to create better usage guidance for photographers, photo agencies and publishers to include copyright and attribution information in image metadata. For more on how to best implement IPTC metadata, refer to the IPTC Guidelines."
Forum discussion at Twitter.