Can I use pictures of professional golfers found on the internet for teaching golf

If it's for your personal use in teaching only, and not for any wider circulation, perhaps. Contact the publishers where the photos appear, and ask if they would charge for the use you're describing. (Images on the Internet have extremely poor quality resolution, and would look grainy, but might be sufficient for your limited purpose.) In either case, you can't be assured that your use would be considered "fair use" and therefore permissible, since your use, while educational, isn't nonprofit educational (which is one factor that might make it fair use), but (I assume) commercial educational.

But if the use is for publishing and disseminating more widely: No. The photos are in all likelihood protected, proprietary material (owned either by the photographer or the entity that commissioned them), and using them for commercial purposes without first obtaining the copyright owner's permission is copyright infringement. Furthermore, you would probably be infringing the golfers' right of publicity, especially if they're celebrities.

You have three alternatives. In descending order of preference: (1) Contact the publishers (or website owners) where the photos appear, and ask if they would charge for the use you're describing and, if so, how much. (2) Use models (maybe volunteer golfers whom you know or local college athletes) and a good amateur photographer to take your own photos. (In that case, get full releases from the models and the photographer.) (3) Contact a stock photo house, who might have the kind of photos you want and license them to you for a modest fee (if any).

Fore! (Sorry, I couldn't resist that.)

THE INFORMATION PRESENTED HERE IS GENERAL IN NATURE AND IS NOT INTENDED, NOR SHOULD IT BE CONSTRUED, AS LEGAL ADVICE. THIS POSTING DOES NOT CREATE ANY ATTORNEY-CLIENT RELATIONSHIP WITH THE AUTHOR (WHO IS ONLY ADMITTED TO PRACTICE IN THE STATES OF CALIFORNIA AND NEW YORK). FOR SPECIFIC ADVICE ABOUT YOUR PARTICULAR SITUATION, CONSULT YOUR ATTORNEY.

The following is not legal advice and should not be relied upon to take or refrain from taking any action.

Query: If I can't use the exact photo that allows the pro to be identified, can i "photoshop" the photo so the form of the swing is still evident, but the pro is unidentifiable?

Answer: Mr. Levitan has already described the right way to think about what you want to do. In short, you can't use the image of someone else for commercial gain without their permission (state laws vary -- some protect only living persons, some protect only celebrities, some protect everyone) and you can't use someone else's photograph without a license from the owner of the copyright in the photograph.

Altering the photograph so the identity of the person is unidentifiable takes care of the first prohibition but not the second.

In legal lingo, by altering the photograph you are creating a "derivative" of the photograph, that is, a new work based on an old one. Only the owner of the copyright in the original photograph has the right to create derivative works of his or her photograph (with some non-relevant exceptions). This "derivative" right ensures that the creator of a copyrightable work is compensated for subsequent creations based on the work (think of a movie based on a book -- the book's author must first grant permission to the movie producer).

There are a number of companies that license the right to use photographs. I imagine that you could track down enough photographs for your purposes and if necessary, as Mr. Levitan suggests, shoot some photographs of your own.