I transferred from using a mythtv backend to a masterbacked and since then I've not been able to see my artwork. 
System configuration: One masterbackend server & three servers holding both movies and tv series, none of which were recorded, and three mythtv frontends. All are connected using nfs.
Mythtv: All machines using Mint 18.2 / mythtv 2:0.28.0+fixes.20160413.15cf421-0ubuntu2.16.04.1
I've been using mythtv for about 3 years so I'm pretty well up on storage groups, permissions, etc. but since converting to a masterbackend server none of my artwork is showing up.
I've searched the database using myphpAdmin and I can find nothing indicating where the artwork is located other than the storage groups. SO, If the storage groups are pointing to the correct directory and the permissions are correctly set why the problem? 
Additionally, if I add a new movie the mythtv correctly searches for the artwork but only displays the coverart. No fanart. 
The same thing happens when I reset & retrieve details on existing movies, etc.I've been dealing with this problem for about 3 months. I've frustratingly searched the net, dam Google to..., oh well, and everything is either out dated or the search returns are numerous and usually useless. Being 72 years of age I long for the good old days. Before Google!
Before the conversion everything worked perfectly. Being exceptionally stubborn I don't want to switch back so I would appreciate any responses from users who could assist with my problem. Solutions would also relieve my increasing blood pressure.
