SERIOUSLY? What Bill has been looking at is a .pdf file.
It was not an "attachment" (as stated by Bill)
and it is not a protected image. What was included in the original email was a LINK to a PDF of a presentation. By far, the simplest thing for Bill to do is to click on the link and download the entire PDF. On my Mac, all you do is hover over the open PDF
and a button bar appears that includes a download icon.
Once that file is downloaded, you may be able to extract the image (if you have the full version of Acrobat) or you may have to use some of the screen shot tricks that others have discussed... but it isn't "protected"
and it isn't very hard to do...
Of course, you could also be polite and email the author of the presentation that you are pulling photos out of and ask for a copy of the photo
😉. A little hunting at the parent web site shows that would be a Mr. George Trandel, who presented this clinic in February of 2018.