For images, a CC marker — a graphic or line of text stating the license — should be displayed on or near the image. Markers should ideally include the CC icons and full URL to the license. For plain text captions, the CC icons may be replaced with the name of the license (e.g. Creative Commons Attribution) or the abbreviation (e.g. CC BY). In both cases the full URL to the license should be included. A copyright notice stating the author(s), date, and copyright should also be included.
How to create your own image marker
source: Christina Xu
It is possible to embed licensing metadata into certain kinds of image file. Creative Commons recommends the use of embedded XMP for this purpose.