Over the years I have so many pictures stolen from my blog, or before in pre digital times published without my permission, that I just do not care anymore.
A few years ago I went into a bookshop and opened a local guidebook, and found the author had generously scraped my blog. The publisher told me they did not pay for photography, and the author had told the editor that the pictures were taken by him. I could not be bothered to go down the legal road for such small pickings. I sent prints of the originals to the publisher, so I guess the author had some explaining to do.
A local council scraped my blog to illustrate a couple of medieval castles in their comune, and a site dealing with medieval history has also visited my Blog to stock up on pictures.
Occasionally a student will Email me to ask permission to use a picure in a thesis. I got a tee shirt for a picture used in an exhibition concerning mazes, in Vienna a few years ago, after they asked permission.
Gone are the days when a check would arrive in the post for published pictures, often without asking, or knowing that a press release picture had been published.
I do not earn money from photography anymore and with the current prices, it is not worth the bother to chase picture thieves for money. It would be a distraction from my more remunerative Engineering work. Unless you are commissioned to photograph something, photographs have close to zero commercial value. I have recently donated my performing arts archive to our provincial theatre's archive. I made digital scans of the things that interested me first.