Are you in the old PB format or new one? If the old one, hover over the photo, you'll see three links show up in a drop down, right click over the last one & it will copy it. With the new format, click on the photo to prop it up, on the right you'll see those same 3 links. Right click over the last one (bottom one), again, that's the image link. Copy it & then go & paste it in your text box when you right a reply on here.
Hope that made sense.
To see if it worked, you can click on "preview post" & it should show you.