How to create 2x lottie with images for retina?

I have lottie with images. And I need those images.
How to create the 2x lottie file for retina displays?
Should I just link 2x image in animation and reduce it 50% ?
Or do I scale whole animation to 2x and reduce it to 50 in the web page?
How to go about it?

What is your starting resolution in AE?