List your sources in a credits screen at the end of the video.
If possible list your sources at the bottom or side of the image (example). Otherwise, include a list of citations alongside the image where ever it’s uploaded (e.g. Flickr, Blackboard).
Powerpoint you create: List your sources in a slide at the end of the Powerpoint presentation, with in-text citations throughout your presentation as applicable. You could also provide a print copy of the sources you used to those attending your presentation.
Websites you create: