I'm a amateur photographer, often volunteering at events. I befriend other volunteers and visitors to these events on Facebook. I would often take pictures of everyone, the volunteers, visitors and entertainers. Event rules and laws rule that I own full copyright to the photos I take and I'm allowed to share them on social media and I am not allowed to hide the photos behind a paywall. I am not allowed to sell the photos. I always fully comply with these rules. I will always be careful not to share potentially embarrassing shots. I will share 'behind the scenes'-photos with volunteers only and shots that put the event in a good light will be accessible to the public on my (Facebook) wall.
I have noticed various acquaintances (often non-photographer fellow volunteers) set my photos as their profile picture. I love that. I’m generally okay with that, even if they re-upload it.
Some other acquaintances will download and re-upload the pictures, as if they were the owners. These are pictures I took, I created them. They seem oblivious to the fact that their face being on the photo does not mean they can use it everywhere.
Now, I don't intend to sue. These are friendly acquaintances that I intend to stay on a friendly basis with. I merely wish to receive credit where credit is due (the photos are licenced under CC-BY-SA). I do not receive or want to receive money for my services, I enjoy taking photos at events, but I also do not appreciate someone just taking what is technically mine. The exposure is what enables me to do my hobby. They do it to other photographers as well. One has a profile picture with a big watermark saying SAMPLE, looking like it was taken at a paid photoshoot.
What I want to achieve
I don't want or need money, but I certainly like the social media recognition. That exposure is what gets me invited to events. I would like to receive credit where credit is due and for my acquaintances to stop re-uploading my photos.
Assuming I found out that an acquaintance reuploaded a particular photo, how can I talk to them about them unintentionally damaging me and ask if they can give me credit without this situation turning awkward?