Same link over and over - question

We have a blogger who is constantly inserting a new photo, almost on a daily basis and a link back to his blog. He starts a new thread for each one of these, but really contributes nothing in the way of content to our forum.

Our question is if this guy has 100's of these sorts of threads posted to our site, will their be any affect on our SEO due to the diluted value of having the same link over and over without any supporting text in these posts?

Well, it is certainly preferred to only include relevant links. But it sounds to me like he is spamming. Or is the photo itself of sufficient quality, like a photo blog?

Always just a single photo, usually a different one with no text except the link which says: "Read more at..."
We know the fellow and he does post sometimes, but all threads that he starts link back to his blog in the manner stated above.

Would you consider him a spammer?

Do the pictures add value on their own? If not, I would consider them spammy posts, and I would ask him to stop.

In fact, even if the pictures are great, I think I would ask him to provide summary content, or else cease making empty blog posts (in the nicest way possible, since he may in fact have positive intentions).

We have many, many pictures anyway and what he adds is usually a re-hash of what he's already posted in the past, so no...they add little value. The better ones he keeps on his own blog.

My thoughts exactly. Any suggestions on how to ask using SEO as the reason? Keep in mind that he has a blog and may choose to give us negative exposure if we handle it the wrong way.

I would delete all theses posts and kindly ask him to stop spamming his blog. If he doesn't stop. BAN.

I would ask him to add text if he wishes to keep posting them. Tell him it's a guideline you have for your member blogs. Also - go ahead and publish some rules.

Then ask him if he would like to revise previous posts, or if they should be disabled.

Don't be afraid to offend someone if your request is reasonable. More likely than not he is aware that he is simply building links to his site, for his OWN SEO purposes.