File:Flickr icon.png

Summary
Flickr 'dots' badge, from https://help.flickr.com/en_us/brand-guidelines-r1KCpZZvS. Their usage guidelines, cut-and-pasted from that page:
 * Do not use our logo in a manner that implies official endorsement from Flickr.
 * Do not alter the logo in any way (dimensions, color, overlay, stylize, etc.)

I have selected "I do not know the license" as I am unsure what the correct license is for an icon that is a brand image but is permitted by the brand owner to be used in accordance with specified guidelines. This is also why I uploaded the image at 1024x1024 resolution, to respect their "do not alter the logo in anyway" requirement.