I want to share a link to my own website on Facebook, so I added the necessary og: tags to the <head> section.
Checked it in the linter, and it displays everything I want it to display.
When I actually want to share it in the newsfeed (as in copy and paste the link into the status formular), the image is ignored.
Here's a sample link: http://iamschulz.de/video/4
Does it break the image size requirements? If so it'll still be detected by the debug tool, but won't actually be rendered in the news feed
Images must be at least 50 pixels by 50 pixels.
Square images work best, but you are allowed to use images up to three times as wide as they are tall.
An image of (e.g.) 100 * 350 won't be displayed because it violates the 3:1 ratio.
来源：https://stackoverflow.com/questions/9213912/ogimage-ignored-when-sharing-link-although-accepted-in-linter