The answer is “surprisingly tricky at times”. Every day on this blog I post my photo Photo of the Day which can be drawn from any one of a dozen or more websites. If something catches my eye I save it then every evening the last job of my day is to delve into my archive and pick out something to post. It is really important to me to credit the original artist , sometimes the information is on the source but more often than not images are posted with absolutely no credit whatsoever (Reddit, I am looking at you here!).
So what options are open to me? Exif data with all the artists info is nearly always stripped when images are re-hosted to save precious kb’s of bandwidth (imgur is especially guilty of this) which only leaves a reverse image search. This usually turns up a result but if an image has gone viral the search can return 10’s of thousands of hits rendering it impossible to pinpoint the photographs origin.
To me this raises an interesting point about how society views photography, that it is in essence a commodity that doesn’t warrant the credit of its creator. I can think of no other art form where this is deemed OK. You would never hear a song that didn’t have the information of the recording artist close to hand. Every sketch and painting is displayed with the artisan’s information nearby. Yet if it is a photo there doesn’t seem to be the moral imperative to ensure that the individual who laboured to create the image deserves recognition.
Perhaps this is a sad indictment of how society views photography. Cheap, disposable, and unworthy of merit.