If you are a regular blogger sharing content on Facebook, you have propably noticed that changes on your homepage might not get reflected on Facebook, this is all related to opengraph cache mechanism in Facebook.
Let’s assume that you have a URL like ‘mydomain.com/mycar.html’. This page is describing your car, and you have uploaded a picture of your blue car. Modern Content Management Systems like WordPress, Typo3, ghost.org, will automatically include the so called Facebook Opengraph tags, means that your code will give hints to Facebook, which meta-data and what picture should be shown.
However there is a caveat: and that’s Facebook’s aggressive image caching. Facebook has to deal with millions of pictures and they have to ensure best performance on a global scale. Hence, the first time you are sharing your URL with Facebook, their software will cache the respective picture.
If few weeks later you have changed your car, and your are updating your blog to show the new red(!) car, it will be very likely, that Facebook is still showing the original blue one. Even if the URL of your image might have changed, this might not necessarily impress Facebook.
But there is an easy way to control this issue and to force Facebook to delete all information, related to a certain URL. In other terms Facebook is offering a quick and easy tool, to delete all meta-data (including images) cached for a certain URL.
1. Go to https://developers.facebook.com/tools/debug/
2. Enter your respective URL (don’t forget to add http:// or https:// respectively)
3. Then hit ‘debug’
On the next screen you have the possibility to either “Show” the stored information, or to “Fetch” new information. Fetching means, that you are able to force Facebook to review your URL again, and to update their records.