Copy image as Base64 от Syd Lambert

This extension adds an option to the context menu when right-clicking on images to copy them to the clipboard in a Base64 format data URI. All images will work, but the primary supported formats are:

• PNG
• JPEG
• GIF
• SVG (svg+xml)

This'll work with pretty much everything, apart from when sites have strict CORS & security rules. Funnily enough, this site in particular is an example where their security restrictions block you from extracting image data, so you can't use the extension on images here. I think it's a silly restriction but they probably did it for some specific security reasons, and you can't really fault them for putting security first in the addon store. Rest assured this seems to just be a rather unfortunate coincidence, it's quite rare to find sites that have such restrictions.