This typically happens if the property has previously been shared on Facebook at a time when the listing was not publicly available; Facebook must have scraped the url and shown the property page instead of the listing which would have the house image.
This can be resolved by:
1. Going to https://developers.facebook.com/tools/debug
2. Enter the URL that is being shared
3. This will show what Facebook has scraped for the URL
4. You can then request Facebook invalidate their cache on the "Batch Invalidator" tab
5. If the URL is scraped again, the updated image should appear.