Thanks for that.. It's smoother than what I had and more consistent. I measure 0.22sec on pc (for comparison) and about 0.28sec on my slowest device.
I added dt to get it the same across devices, and a timer to check. edit: and x4 sprites because I need 4 at once.
I had been playing with scale and even animation frames. Scale is jumpy and animation frames play back at different speeds on different devices.