I'm glad you now have it sorted.
...possible to merge the artist photos
I use the feature & in my case there are duplicates between the folders & I didn't want them merged. I checked a few discogs vs lfm ones and there seemed to be some duplication of images in those two sources as well. You can always merge them yourself into the lastfm download folder. I can understand you might not want to do that, but at least there is a solution. If you decide to try, I suggest using a back-up copy in case it doesn't work out. Make sure 'Image Filter Lastfm' in panel properties is off else the discogs images won't display.
isTrackRevAvail should be fixed in the next version
It's used to set the grayed status of "Track review" on the load menu.
Also fixed for the next version is a regression in set language.