I'm in the unusual place of having to take over a website that has poor images, thanks to a combination of a poor photographer and a clueless project team, etc. I've never used stock images before but seems the most logical place to try to get images that match our site's objectives (office furniture and services). We do have some good images of our work, but very little of some the services we offer (like moving). Supplementation needed and no time or budget left to reshoot with a professional.
So, it seems the best thing to ask the photographers who contribute to the sites, which are their recommendations.