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?
Although Facebook seems to ignore the picture set to an empty string in the Graph API call, setting an Open Graph tag for the picture which is an empty string seems to have done the trick.