If you look at the pictures most of them have a click-through source to the author (especially if the picture is shared on Flickr, where the photographer can chose whether they want their photos to be share-able or not), and for other places you can see the source either in the post or if you click on the picture (in the description). I strictly avoid posting from photographers who openly told me they don’t want their photos shared around the internet (J.P. Foster,walkkyoto on Flickr, Ei88 on their blog and some others who made their photostreams private for this purpose). So in short, yes.
If you see a picture here that is missing a source or you feel like it shouldn’t be posted here, please let me know. The same goes for my facebook page too.