Simplest way to get a public URL for a photo from Photos App?
Right-click a picture in Photos, Share [More... if you don't see all the options]

Flickr has a built-in uploader option, but not Imgur.



There are some tools listed on Imgur Help, though I haven't tried any of them personally.

Otherwise the 'simplest' way to get pictures from Photos to Imgur is to drag from Photos to the Desktop, then from the Desktop to the Imgur page... [then throw away the one on the Desktop]

Alternatively, Gyazo has an app that will let you instantly upload &amp; add a link to your clipboard.

Dropbox allows you to right click &amp; share a link to any file stored in it - though you'd have to follow the 'drag to Desktop [or Dropbox]' procedure as above, without then discarding the original.