Google Image Search has added a new filter option to the mobile version of image search. Right under the search box, it now gives you quick filter links to filter for the latest images, GIFs, clip art, colors and copyright. You can even drag the bar to the left to show more color filtering options. At the end of the filter options is an option for filtering for “labeled for reuse.”
Here is a screen shot:
After you click the filter — in this case, I clicked red — you get filtered results based on your selection:
Google has not yet announced this new filter option, but it seems it is now rolling out in the mobile image search results.