At the end of Serenity, Jayne is seen stuffing his face.
More after the break...
One more screencap:
This cat and dog graphic is very reminiscent of Kaylee's Cartoon brown overalls. I'm wondering if they reused it here. I also think I see some cyrillic, but I could be mistaken as well.
My Photobucket Album for Jayne.
Serenifly Costumes site for Jayne.