I have tried both, and I ended up making my own category system combined with elements of various systems.
00-09 - Fringe Characters
10-19 - Sherlock Holmes Characters
every x8 (08,18, 28, etc.) is the number for a physically attractive women, preferably a sexualized women as well, as the 8 resembles an hour glass figure. Images there are women like Boa Hancock (One Piece), Sasha Grey (movie star, ex-porn star), Black Widow (Marvel), Wonder Woman (DC).
regularly, an image also has a number-shape association. 41 and 51 are Hawkeye (Marvel) and Arrow (DC) respectively as 1 looks like an arrow. 55 then is Superman where 53 is Batman, as 5 resembles an S and 3 could be a bat. 00 is an Observer (Fringe), as it looks like two eyes. At 20 however, the 0 resembles a balloon, for Monkey D. Luffy (One Piece). 56 has the 6 resembling Bane’s Mask (DC) where at 86 the 6 resembles Madilyn Bailey’s Guitar (musician) and the arm with fist of the Hulk (Marvel) in 46.
Associations can also be with the person, Shanks (One Piece) has number 21 as he has only one arm, same reason for Nina Sharp (Fringe, 01). 99 is Leonardo da Vinci as he is known as a man who was a master of many trades (so he got the highest number). 23 is Roronoa Zoro (One Piece) as he fights with three swords.
Inconsistent, but still it has proven to be rather rasy for me to remember.