Would chin filler be a good fix for my double chin? (Photos)

The answer to your question really depends on your goals. If you want to slim down your double chin, KYBELLA® is a simple injection that's intended to dissolve the treated fat cells. However, if you're concerned that your chin doesn't have a strong enough profile, then you may be a better candidate for chin augmentation. I suggest scheduling a consultation with a board-certified plastic surgeon who offers both options to get a complete evaluation and recommendation of the best way to achieve your goals. Good luck to you!

A long acting chin filler such as Voluma would definitely help your profile. At a later date you may even elect to have a chin implant, which is permanent.
A liposuction of your submental area of your neck would also be indicated, and this can be done under local anesthesia at the same time. This is a minor procedure requiring minimal recovery, such as a weekend. 
The area that is liposuctioned will look better then it does now at a week postoperatively, but the swelling will continue to subside for several months. 
The combination of the chin filler and liposuction would change your profile appearance dramatically.
Thank you for your question and photographs, and best of luck to you.