>>5752017>well designedWhile everything else mentioned in this post plays a part, I think the main catch is this: design.
Not as in "this character has elf ears and this one a golden armor that shoots boobs", but more of a graphic logic to it.
When you copy a picture, you are copying reality and all of its weird angles, corners and masses.
When you draw a picture you are improving reality with cool shapes, balanced masses, ideal silhouettes.
Even le facebook copies can look cool if you do more than copy and actually abstract what makes the picture attractive and ramp it up in your illustration.