I have no problem with people using my photos, provided they ask first, and provided they don’t then bugger them up.
These two things don’t always happen. If I am not asked, then of course I probably will never know that they have been stolen. There is the occasional exception; but you just have to accept that if your put photos up on the internet, people are going to steal them and you are unlikely to find out.
But the real pain comes when you provide the photos, and the photos are abused. It’s almost, but not quite, like seeing your children being tortured.
The most painful example arose from a request from the windsurfing club for some shots that they could use for advertising. We set up a special shoot and captured some great images. The light was right, the wind was right, and the camera was pointing in the right places at the right time; fantastic. Really happy with the results which could have been printed at A2 or higher on laminated plastic and would have looked amazing. Instead they were printed on cheap corrugated junk and looked utter shit; the photos might as well have come from an ancient phone camera. I die a little inside every time I pass them.
And now I have been pierced through the heart again; and it’s another windsurfing shot. You may recall this from a few weeks ago:

A magazine in Bangkok asked if they could use it. No problem; good to publicise the sport and the club, what could go wrong? Well, this:

Not content with trying to make the sea look bluer than it was via a ham-fisted Photoshop assault; they decided to black out the face of the rider. The less charitable might conclude that; given that the target readership of their magazine is middle class Bangkok Thais, they didn’t want to show a suntanned face on the cover. I will give them the benefit of the doubt and conclude that they are useless wankers that have ruined my photo.
They promised to credit the shot to Pattaya Days; I am hoping that they didn’t bother.