It's a real pity. Thanks Pone, I tried too to get it working. Darn HTTPS 
What I have done is put this in my tools for CTRL+2 (2nd in the list). Which opens the images in your browser. You view the image, then drag it to the artwork area in the mp3tag UI. Save tags.
Here's the code for the tool:
https://www.google.ie/search?hl=en&safe=off&site=imghp&tbm=isch&source=hp&biw=1656&bih=1190&tbs=imgo:1&q=$replace($trim($trim($repl($regexp($regexp($regexp($regexp($regexp($if2(%ALBUMARTIST%,$if2(%ALBUMARTIST%,$if2(%album artist%,$if2(%band%,$if2(%ALBUMARTIST%,$if2(%artist%,$if2(%artist%,%discogs_artist_name%))))))),(?i)^(va|various artists|v\.a\.)$,various),(?i)the,),(?i)''s( |$),$1),'(?i)[^\w]+(featuring|feat|ft|presents|pres|and|vs|w/|\+|/|&|www[^\s]+|[^\w\s])\.*', ),'\s+', ),',',)) $trim($regexp($regexp($regexp(%album%,'\b-\b|_', ),'(?i)\[.*\]|cd\s*\d*|[^\s]+.com|\bep\b|feat\.|ft\.|\bom\b|\boriginal\b|\bclub\b|\bmix\b|\bremix\b|\bthe\b|vinyl|web|www[^\s]+|[^\w\s]',),'\s+', ))), ,+)
It includes the option in google images to show image size so no need to hover/click on images.