1 Death of Insanely Overpowered Fireballs: Never mind where the photo came from. Can you find this missing woman?
2 Charon: I know where all dead people are.
3 Death of Insanely Overpowered Fireballs: She’s dead??
4 Charon: You do know we’re all personifications of Death, right?

Often I write strips thinking that the context is obvious because of course everyone remembers the story up to the present point and specifically what happened last time we saw these characters.

My original script, right up until the time I was assembling the photos, began:

1 Death of Insanely Overpowered Fireballs: Never mind that. Can you find this missing woman?

I revised the first sentence to be more explicit as to what Fireballs was saying to never mind. I'm not sure strictly how necessary this is, or how many readers it benefits, but I'm pretty sure it's more than zero.