Do not assume it’s free to use just because it’s on Flickr’s CDN or lacks a visible notice. Photos are copyrighted by default, including on Flickr, unless the owner has clearly licensed them otherwise.

A practical way to trace a Flickr CDN image is to use the number before the first underscore as the Flickr photo ID. In your example, 14742720206 can be appended to http://flickr.com/photo.gne?id= to locate the original photo page and check its stated license. Reverse image search can also help find the original source or credited photographer.

Based on the community answers, this specific image was traced to a Flickr page that listed a CC BY-NC-SA 2.0 license. That means reuse is allowed only under that license’s terms, including attribution, share-alike, and non-commercial use. If the image has since been removed, that makes verification harder, so you should not rely on the CDN link alone.

Fair use is limited and context-specific, so it’s not something you should simply assume for presentations or republication. If the license is unclear, ask the owner for permission or use an image with an explicit reusable license.