With the marked increase in movies and TV shows that are based off of comic books there is the equal increase of the outcry around how the comics are adapted for the screen. At the same time I feel like you will hear one person yelling about how an adaptation handled a certain character and then only a short while later someone will point out how this one comic run fits perfectly with this adaptation of the character. It’s just that there’s decades worth of comics to draw from.

Not the image I first saw like this on Facebook… the one I liked had different TV and movie jokers over time, and the comics that they looked like.
A prime example being the new Joker as portrayed by Jared Leto. When images were initially shown of the new Joker people got up in arms saying it was not really the Joker, but then others started showing that actually there are comics that fit with this new look for the Joker. Then the question is raised about what from comic books are sacred when considering an adaptation if there can be so many differences between the comics?
Now I have only been reading comics in the last few years really, but even so it is easy to find places where there are inconsistencies between stories. Now in comics this can be explained either through the use of alternate universes or from just continual reboots of the stories themselves. So what are the things that usually don’t change?