I don't think the price is the right fight to fight. Even if it was cheaper than usually doesn't mean the buyer can't expect accuracy? If the seller had advertised it as a lesser product, sure.
What confuses me too is... was it the exact costume being offered in the shop? I'd imagine if I, as a commissioner, offered to make a specific costume in my shop I'd do a little research about it beforehand...
About the pictures: If the seller didn't think the picture she was sent was enough, why not ask for more? Don't people always harp on how COMMUNICATION between commissioner and buyer is the key to a satisfying transaction?
I agree it's not the commissioners job to search for pictures, but if they felt like they couldn't do their job right with the picture they were provided, why not talk about it?
There's absolutely NO excuse for the commissioner to feel like the buyer deliberately wronged her.
Though with the way she behaved herself in this thread and the other one (holy sh*t can you say condescending and arrogant?) I may be a teeny bit biased against her