I'm using the Graph API to post to a user's wall via a 3rd party website. The update contains a link to said 3rd party website. (In functionality, it's kind of like just putting a Facebook "Like" button on the 3rd party page, except I want some more finely-tuned control over how the caption looks on Facebook.)
I am not specifying a picture for the post. When the post is created, Facebook's bot automatically connects to the 3rd party page specified in the link and selects an image to use as a thumbnail. Sadly, the image is almost never relavant, and I would just rather Facebook not look for a thumbnail at all.
I can probably put some Open Graph tags on the page to help out Facebook's bot, but I don't see a way to use Open Graph to specify that you'd like to have no image, and that Facebook shouldn't choose one automatically.
Any way to do this?