(2014-08-25, 04:28)AU Jim Wrote: 1. When scraped by Universal Music Scraper - what is the typical resolution/quality?
I'm not really sure, to be honest - you could ask in the UMS thread to get a definitive answer.
Much of the remote music artwork in my library is coming from fanart.tv, and a quick look around that site suggests that "Artist Thumb" images (thumbnails in XBMC-parlance) are often 1000x1000, while "Background" images (fanart) are 1920x1080.
UMS may also use other web sites as an artwork/metadata source, and I've no idea what kind of quality is available in this case. The UMS thread would know, though.
(2014-08-25, 04:28)AU Jim Wrote: 2. What is the optimum resolution/quality
That depends, as increasing the resolution of the cached artwork has consequences - more storage, increased processing power, more memory usage.
For these reasons, low power devices often default to really low resolutions when caching artwork. My advice would be to use as high a resolution as your hardware can support, and since your device is a NUC then 1080 for both fanartres and imageres should be fine, though it may cause the UI to be a little more sluggish than when you use lower resolutions.
Note that these two resolution settings have no influence over the quality of the artwork that is found by scrapers such as UMS, they only determine the quality settings of the cached artwork. It is the cached artwork you see on your display, not the original source artwork.
(2014-08-25, 04:28)AU Jim Wrote: - i may just decide to go and download album art for all my music a keep it local - is this a good idea in hgeneral anyway?
Relying on remote artwork is, IMHO, rarely a good idea, given that remote artwork available today may be gone tomorrow, something that becomes much more apparent when sharing a central library (MySQL) as, by the time one or more of your clients come to display the artwork (downloading into their local cache), the remote artwork is quite often gone (deleted, site offline etc.). This leaves the client displaying a blank image, which needs to be replaced in the library (and re-cached on all your clients, if you were to replace it with another remote image!)
I only have remote artwork in my music library as I don't really care about music on my test XBMC client (a Raspberry Pi - I use a Squeezebox to listen to music, not XBMC) and only scraped the music library for test purposes. For my movies and tvshows, all the artwork is local, so that I'm not left depending on transient remote artwork.
(2014-08-25, 04:28)AU Jim Wrote: 3. As mentioned the album art looks way beter when displayed as a larger image - for eg. when i press "Info" - So it's maybe the way XBMC processes the image when displayed very small ("Wall" view and "Show Icon Label") ?
That's entirely possible, it all depends on the scaling algorithm being used by your hardware. It could be cheap and nasty, which results in very poor image quality. You'd need to raise that as an issue with the developers (once you've determined that the cached image is actually good/high quality to start with, and is then being trashed when displayed at the smaller size).
(2014-08-25, 04:28)AU Jim Wrote: 4. Is <fanartres>1080</fanartres>
<imageres>1080</imageres>
good settings to have? ir 1080 on both ? is that a good setting?
I use 1080 fanartres and 720 imageres myself (R-Pi 512MB), which means those 1000x1000 artist thumbs are being squished down to 720x720 in my texture cache.
If you want to keep the cached artwork as close to the originals as possible, then 1080 for both fanartres and imageres should do the trick.