She's got the same coloration as my cat Beverly, only she's lean. She's very energetic, even at age 14. She'll follow me, my mom, or sister around the house, always interested in whatever's going on. And if we have a visitor, even something minor like UPS, she'll burn some calories hiding scared under a bed for a few hours.
I can't imagine that she weighs more than 10lbs.
In terms of weight, your cat looks more like Scotty, Beverly's brother. He had, well, they looked almost like jowls, except they were stomach jowls. He was hilarious to see trotting - those flabby jowl things would just bounce side to side.
Scotty and Beverly