I remember when I was using Graph v2.8, I could set custom picture and caption for link. Now it is impossible for v2.9. Is there some kind of workaround without specifying og: tags.
How it was on v2.8:
How it is now on v2.9:
Unfortunately there is currently NO publicly known workaround.
According to facebook developers blog:
As part of our continuing efforts to stop the spread of misinformation and false news on our platform, earlier this year at F8 we announced an important change to our Graph API: Graph API version 2.9 includes a 90 day deprecation of the ability to edit previews attached to link posts.
https://developers.facebook.com/blog/post/2017/06/27/API-Change-Log-Modifying-Link-Previews/
The feature works for API version < 2.9 until 17th of July 2017, though.
来源：https://stackoverflow.com/questions/45103086/facebook-graph-publish-posts-with-link-and-custom-picture-not-working-on-v2-9