Error when deleting a photo

I'm new to the platform and currently setting up my property. When running the listing analyser, it through up that a photo wasn't compatible so I'm trying to delete it. However, it keeps showing the following error message over and over;

Error! (User Unauthorized)

What just happened?

We tried to do that operation, but ran into an error: You cannot delete this file because there are leases associated with it.

Has anyone else experienced this and know how to sort it? I've tried removing the tags from the photo, removed it as the property logo, but no luck so far.

Thanks in advance. 

This took some digging... it seems that you're trying to delete a photo that's currently in use as the header or the theming logo. 
Look at a preview (or signed guest copy) of your Renter Agreement to see which photo is in there. You'll then want to go to Settings > Theming  and remove any of those small photos from being theme logos.

Once that's done, you should be able to delete the pictures from the Properties > Photos page.