Depends on the photographer and what is being sold. I have seen prints by wellknown photographers of traditional musicians go at a premium in the collectors market

https://www.mutualart.com/Artwork/2-Works-Fiddler-s-light--donegal---Portr/FFCEE3F8D5C5FC9B

and digital prints at

http://www.christymcnamara.com/product/paddy-killoughery/


Licensing can vary, depending again on photographer, subject and use.

Years ago I supplied a series of photographs of traditional musicians who had died during the year, for use at a televised award ceremony. The producer asked for an invoice for their books, the broadcaster demanded that, but never paid. Go figure.

But putting photos online is like giving away your work. Once it's online people think it's free for all, including large professional organisations.

I must say, it's off-putting but I rarely put a snap online without obnoxious watermarks these days. I prefer to make photos available through the county library (although Clare Libraries' photo server is now down due to a technical problem, there are a few thousand there) or ITMA.