Album art don't work on n-stream

I have a Synology 212j running the latest DSM 4.0 firmware. Embedded album art in FLAC files is not recognised but an image file in the same folder is. Make sure that the media server settings in DSM are correct. In the media server window, go to the browser settings tab and check the box next to the "Set images with the below filenames as music/video cover". Note that the filenames in the list are case-sensitive; so, if the list includes "folder.jpg", it will not recognise "Folder.jpg" (or "folder.jpeg" unless these names are also included in the list.

The only problem I have had is that the full resolution image file does not appear in n-stream. I normally use 500x500 images and the displayed artwork is clearly lower. Bizarrely, if I check the box marked "Transmit low resolution images instead of the original images" the the displayed artwork is a higher resolution (but still not as high as the original). This appears to be a problem reported by Synology users for various media players but I have yet to find a solution.

Yes, after changing the synology settings, it is working fine now though I am not happy with the resolution. Will try your suggestion.

I've just updated to the latest DSM 4.0-2219 firmware which was released on April 17. According to the release notes, the changes to the media server package included: "Added an option to transfer the album or video original cover image to DMA devices." I cannot find any specific setting in DSM which enables this option.

I tried changing my settings to remove the "Transmit low resoltion images ...." and deleted the image cache on my UQ but it hasn't made any improvement!