Why is there a juggler in the cover of Queen's album 'Innuendo'?

The rock band Queen used part of his artwork ["Juggler of Universes"] for the cover and backcover of their 1991 album Innuendo, as well as their singles from that album. Alice in Chains used part of his artwork for their album Alice in Chains, as well as their singles from that album.

https://en.wikipedia.org/wiki/Jean_Ignace_Isidore_Gérard

It borrowed heavily from artwork J.J. Grandville.

QUEEN Innuendo (Scarce 1991 UK Parlophone label promotional-only 8½" x 6" greetings style card, featuring an image of a juggling clown designed by Queen and Richard Gray which was inspired by illustrations from J.J. Grandville which was used on the album artwork, on the inside is the full album tracklisting along with the release date).

http://eil.com/shop/moreinfo.asp?catalogid=18113

Jean-Ignace-Isidore Gérard was born in Nancy, France in 1803 and adopted his Grandparents name of Grandville.
As an illustrator he created a legacy of imaginative and fantastic drawings which have been very influential on many cartoonists and illustrators. Two of his finest works come from the books 'Un Autre Monde' and 'Les Animaux'. Queen's innuendo album (and the majority of subsequent single releases) used illustrations by Grandville which were adapted and coloured. It's rumoured that it was Roger's idea to use the illustrations.

http://queen.musichall.cz/en/misc/j-grandville.html