While editing a link you can request thumbnail of the given link at the time.
It uses the Google page insights API to get a thumbnail.

It will be created if the option is actived. To remove uncheck the option.
To refresh uncheck the option. Save. This will delete the data.
Check the option again and the thumbnail will be created again.

Any error in this process will be visible in the error log file
and not visible in the client. This way the link will be saved
and no data will be lost.