When you share your photos or other creative materials on websites like Flickr, you have several licensing options. This flowchart can help you pick the right licence under Creative Commons.
Just follow the arrows to answer the questions about remixing (in the pink boxes) and commercial use (blue boxes) to get the detailed licence you should use (purple boxes).
Creative Commons has an online tool with similar questions, but this flowchart from Creative Commons Australia is a bit easier to use and understand at a glance.
Which Creative Commons licence is right for me? [Creative Commons Australia]