Indeed - though filler's not so much a worry as the amount of content I have and the question of where to divide it. I worked best with my script getting the material down first and deciding how to split it later I fret over chapter titles so it seemed like a plan, not that it's any easier now..
I suppose that in a comic you would divide the chapters based on an individual character's specific goal for that time. For example, if the lead character is on a quest to find a magic sword and he is becoming weak from hunger, the chapter would be about how he is furthering his quest for the sword by finding game or a inn of some sort. The chapter would end after he had eaten and decided what to do next. That is the best way I can think of to explain a break down of a point A to point B plot. All characters should have some sort of primal need driving them at all times, which effects how a character will think in any given situation. If you build your chapters episodic, as if each chapter were a mini-story itself, then the chapters only need to be balanced with a beginning, middle, and end. The length shouldn't be an issue with an episodic chapter, and if it is too short then there are probably some questions that are unanswered. I wouldn't worry too much about chapter titles unless you're trying to send a message using the titles, but then you would need all of the titles written beforehand (ex: all the titles are a poem when combined.) Chapter titles can be tricky because you don't want to give away what is going to happen. I personally just use chapters as story breaks, so I just leave them titled by numbers. (ch 1, ch 2, ch 3, etc) Hope that helps.
It really depends on the update schedule, I think. If they're consistent, chapters can be longer, but if it's irregular, I prefer shorter chapters so I can go back to the beginning of the chapter to catch up if there's been a long gap. In books I do prefer consistent chapter length, if only so I can estimate when I can stop reading (I like to read chapter by chapter) Good luck!
Now this question could be considered for books as well, but since I'm in the stage that I'm divvying up Dark's Watch for better editing and to really prepare it for practice.. well, that's why I ask.
I think of Earthsong and Unsounded, which have varying lengths per chapter, and honestly that looks like it will work for me. But I also see there could be an advantage as with comics like Teahouse, where there's a fairly set amount of content, and I know from reading books that sometimes the varying chapter lengths can also be a pain.