Missing Album Artwork

A couple of things might be wrong here. The artwork piece sometimes get's messed up and it's difficult to find out why......

1. completely rebuild the metadata from scratch by ordering the server to rebuild

2. For the albums which still have a problem try to save without album artwork first and again add the artwork - both by again rescanning In the meta data db

3. If doesn't work remove artwork in the tags, save and put the artwork away in a jpeg file called folder.jog in the sub folder which also contains the album....

i assume you did already do the normal stuff like refreshing the artwork in the naim app, setting the app back to factory settting, completely restart iPad etc...

I would be out of options if all of this doesn't solve your issues.

Unfortunately, your suggestions are way over my skillset. Kind of a computer dummy here. 

I'm not sure that this will work for you, as my setup is a bit different. I too have a Synology NAS, but I store tracks in FLAC, not AIFF; and I use the Naim app on Android rather than on iPhone. But I've seen a similar problem, which I solve as follows. For each album folder, store a copy of the cover image as a JPEG file Cover.jpg in that album's folder. On your Synology Media Server app, look for "Browsing Settings" and make sure that Cover.jpg is one of the filenames for music/video cover. The final question is how to get those cover JPEGs. I never use AIFF so I don't know how they work, but when I rip CDs to FLAC via XLD (a Mac app), if XLD can find the cover information online, it embeds the cover image in each track file. Then I use another Mac app, Metadatics, to extract that image as Cover.jpg for each album folder I rip. Metadatics does a lot more, it's really essential for correcting album metadata for older or rarer CDs that have incomplete or incorrect information online.

Appologies, I also have found this all out in tedious processes of missing sometimes artwork.

Maybe re-indexing of multimedia files on NAS will help?

Good suggestion, but the original poster has album art embedded in the aiff files and the most elegant solution will be to see if he can avoid having to create a folder.jpg files for each of his albums.  

I too am having the exact same problem with some Aiff files. They all have the artwork embedded but for whatever reason, the album cover artwork doesn't get transferred to the Naim software or the individual tracks have the cover art but the large icon in the Naim app shows the symbol the the OP posted.

I think Fernando's suggestion makes the most sense. The Synology NAS does have the option for passing on the album/cover art using a folder jpg. 

It sounds like metadatics makes this a simple chore and is a simple solution.

I suspect that the reason is the server.  Each server will handle things a little differently.  But all seem happy to find a separate jpg file with the artwork and use that.

It's a mix of the server and the UPnP control point. In my experience, the Android naim app gets the cover art in most cases from my Synology NAS with Media Server, even if there is no folder JPEG, but the BubbleUPnP Android app, which I use to control my home office headphone setup from the same Synology source (SOtM sMS-100 -> Schiit Bifrost -> Schiit Asgard 2), needs those folder JPEGs.

Having a file called folder.jpg in each album's folder on your NAS/PC/server does seem to be the safest (?) route.  You can obviously do this manually, but something like Bliss can help do it automatically.

I had this problem to start with, the way I got around it was to ensure all art work was in .jpg format and resized to 174 x 174 pixels, this along with using mp3 tag to ensure the art work was embedded into the files cured the issue for me.