I have over 200 images in my condo and I loaded a condo save to clean up the mess I made from my 1,001 silver catsack opening. I looked around at first and things seemed fine. But I eventually realized some of the images were different. Images of carpet hanging up on the walls or whatever!
This has been known for a while, and the save system is unfortunately very broken still. Just don’t use the save system until they fix it. I don’t think there’s any way for you to get the images back to where they were without manually redoing everything.
The general rule of thumb is to never rely on the condo saves and assume they will be broken sooner or later.
I haven’t had a reasonably sized condo snapshot that wouldn’t go corrupted eventually.
It’s important to save into a new file just so that you keep the older snapshots (given they are fine), and create a new one every time you save.
Also, sometimes your condo after loading a snapshot would look perfectly fine on your end, but to other people it would look like some canvases swapping URLs like you described. The only way to confirm that your snapshot is fine is to ask your friend to join your condo.
Basically, don’t trust snapshots on both saving and loading.