Click the Sync Images button and refresh your browser (Ctrl + R) and your images should appear within 15 minutes.
If the images are appearing blank with a broken link:
A) Click on the image from the Manage Photos tab and click the link to the Instagram Post. If it says the post no longer exists, then the post was deleted and you will need to manually hide / remove the image from Covet.pics
B) Go to Settings in the app and under Facebook Authentication, click Reconnect on your Facebook account. Click the Sync Images button above the images from the Manage Photos page. Wait 10-15 minutes and then refresh the webpage.
C) Go to Configure Channels and delete the Instagram feed. Click Save Changes (if available), and then re-add the feed, and click Save Changes again.
D) Go to Settings in the apps and remove your Facebook account. Then re-add it. Then repeat Step C.
After any step, sync your images.