Getting the share button is not a problem.
However, the problem is in the way facebook selects the image to display with the shared link – currently it offers the first image from the gallery, and not the actual one I want to share. the shared link, is correct and opens the right image, though ..
it may be something to do with the fact that facebook does not launch the javascript on the page when fetching the image(s) – isn’t it worth to just show the picture when javascript is not enabled?