I can only answer in regards to FireFox. Simply highlight the image (any image), right click on it, and select Copy Image Location from the popup menu that should appear.
Try it and see if you get what I got below...
I can do that on Safari, as well. I was trying to figure out how to turnout into a postable image, in the first place. I thought maybe you’d made the screen grab. Or, did you find the image somewhere else? Thanks.