Can I skip the matching cousin shirt without vetoing the Chaos Pigeon?

My cousin sent a mock-up of a lime-green shirt with a startled pigeon on it. Under the bird: COUSINS OF CHAOS. I replied, 'That pigeon has seen the planning spreadsheet.' He immediately added a little spreadsheet to its wing.

Ten of us are meeting for a weekend. He wants matching shirts for the group photograph and has found someone who'll print them for $12 each. Six cousins have enthusiastically sent their sizes. One wants hers as a keepsake but says she won't wear it. Two haven't replied. The order hasn't been placed.

I like the drawing on a screen. I don't want a giant pigeon across my chest in photos that will live in the family chat forever. I offered to wear a plain green shirt so the picture would still look coordinated. My cousin said, 'But you helped design him. Your pigeon will be lonely.'

He's done most of the weekend organising, and the shirt is the part he's excited about. I don't want to ask everyone to change a design they like. I also don't want my one joke to count as a size confirmation. How do I opt out clearly while leaving the Chaos Pigeon available to everyone who actually wants him?