Tough one. First off, can you legally alter the other guy's photos to begin with?

For the show chair, I guess it depends on how much you like her, what the relationship is worth or whether you want to make a point.

If it were me, I'd send her a bill for the show (just like the show that booked the other guy a while back (last year?) and they basically paid you not to work it.

I'd make it clear that if she can't pay, I wouldn't fix the photos.

Of course, once I get my temper up, I'm a complete ass, but it does take quite a bit to get me there and the target of my ire usually deserves it.

If you want to be nice about it, I'd point out that her mistake not only cost you the income, but caused a photographer that apparently either doesn't know what he's doing or was in fog that day to totally screw up everyone's photos.