Flickr lets you assign controls and copyright restrictions to your images. For a free service, they are pretty clear on user rights. A small German business making horse and goat cheese asked to lease rights to a photo on my wifes Flickr site to use for advertising. She appreciated the honesty, and told them to go ahead. They put the image on some small trays, and sent her a stack. This was a image taken with a point and shoot, and heavily photoshopped to remove a fence in front of the animals.
I have my own website, so I'm not concerned about instagram. I have some old scanned images of my ancestors on Facebook, and on Ancestry.com. Those who want them are welcome, and I've also found many photos of my ancestors that others were willing to share.
This is a snapshot of the tray. She gave some to our kids, and keeps one to show occasionally. We've never used it for cheese, we have made goat cheese, but our horse is a gelding, no horse milk