Artwork has been improving steadily in Jaikoz over the last year, especially since the Cover Art Archive was introduced but with hew version of Jaikoz things have got even better.
First some terminology, within MusicBrainz the concept of an Album is represented by a Release Group, then different versions of that release group are known as Releases. A release is the thing that we can actually buy and often varies slightly between countries. So a release group often contains different releases because it is released in different countries with slightly different tracks. Discogs also uses releases and has similar concept of release groups, known as Masters
Until this release Jaikoz checked the matching release for artwork on both the Cover Art Archive, Amazon and Discogs but just for the matching release. But now if we find no match we then check all the releases within the same release group and Discogs masters, artwork is usually the same for all releases within release group but often MusicBrainz does not contain artwork links for every single release in a release group so this change gives a big improvement.
I ran a test over 1000 songs , and matching artwork went up from 782 to 960 !
Full list of changes in this release can be found here