Photo-sharing site Pinterest has had its share of legal troubles in the past, mostly because trying to keep up with every single image uploaded on a daily basis–as well as their origin–is a daunting task. Trying to police copyrights on the site is becoming increasingly difficult as user numbers grow every day. As one writer said, it’s like a never-ending game of whac-a-mole.

But some say that Pinterest isn’t doing enough to keep their users from posting copyrighted material, instead essentially leaving it up to copyright owners and other Pinterest users to seek out the offending photo themselves. The site achieves this by allowing other sites to “opt out” of being pinned, but that doesn’t keep copyrighted material from being shared, and many think the sharing site isn’t being proactive regarding a crackdown on offenders.

One of the main problems is that Pinterest’s terms of use are a bit contradictory. They state that the user must be the sole owner of any material pinned on their account or the user must own all licenses to the material and are legally allowed to share it; in other words, standard fare when it comes to a site which hosts photo sharing. However, the terms get a bit sticky when Pinterest explains that while they want users to pin things they’ve created and are proud of, they don’t want to see a bunch of shameless self-plugging.

“Pinterest is designed to curate and share things you love. If there is a photo or project you’re proud of, pin away! However, try not to use Pinterest purely as a tool for self-promotion.”

That leaves one thing: pinning found photos, ideas, and recipes, which is essentially the very point of Pinterest.

On their part, Pinterest has added certain features which allow for at least a minimal amount of copyright security, a major one being the “Pin It” button, which can be added to your bookmarks toolbar and automatically credits the source of the image without the user having to do anything. They also have an entire section of the site dedicated to copyright complaints and how to go about filing one. The information given says that they have the right to remove your photo if a complaint is filed, but if you contest it and the person who filed the complaint doesn’t seek a court order to pursue the issue within ten days, they will put the pin back up. Too many copyright complaints can get you booted off the site completely.

Getty Images is rumored to have some issues with Pinterest of late because of their failure to police every copyrighted image. Getty has been known to send companies who infringe on their copyrights an invoice for use rather than getting embroiled in a court battle; however, both Pinterest and Getty declined to comment on the matter. Getty CEO Jonathan Klein says they aren’t as concerned with people using their images as they are about people–or companies–making money off them.

“It’s in our interest for people to be visually literate. So we don’t stop consumers playing with our images, we don’t stop kids downloading our images to use in school projects or for educational purposes, we don’t stop the proliferation of imagery, still or moving. Where we do draw the line is where someone is generating revenue, commercial revenue, on the back of our image,” Klein says.

When asked about how Getty responds to sites like Facebook and Pinterest using their photos, Klein said that they’re comfortable with people using their images to build traffic, but they need to have a license in order to protect themselves and the copyright holders.

Last year, Getty acquired copyright solutions developer Picscout for $20 million; Picscout identifies the source of an image as well as alerts copyright holders whenever their image is being used. There’s been some speculation that they are trying to get Pinterest to license the rights to the technology for use on their site, although it’s certainly possible that Pinterest will balk at the idea and claim they can handle the copyright problems with the “safe harbor” rule, which states that photo sharing sites aren’t responsible for user activities as long as they monitor and comply with takedown requests. The chink in the armor is that Pinterest has been accused in the past of messing with links, stripping them of affiliate information. Pinterest also declined comment on that subject.

It seems one of these companies will have to bend just a little bit if either of them wants to get anywhere. As difficult as it has proven to be to monitor who’s using what image on the web, it may be fortuitous for the two image-based sites to work together.