Website update (new theme) and new product images

I am in the process of implementing a new theme on my website (current site is live). The design of the new theme will require all of my products images to be re-created at a new aspect ratio and different background color.

If I update my products with the new product images, they will be displayed on my current site. I am not sure how to get all of the new product images to display on the new theme I am working on and not on the live site.

Does anyone have any tips on how I can display the new product images on my in-development theme and not have them show on my current site?

I am still working on the new theme and would like to see the new product images when I preview, but if I change the product images in the product database they will be changed on my live site.

You can add a demo product or copy one of your products and then archive that product.

I have already copied a couple of products to see what the new images look like, but I have over 200 and don’t want to copy all of the products.

At some point I will need to replace all of the current product images. My preference would be to get all of the product images in place on my new theme without affecting the images on the current site.

When the new theme is ready I could then publish and have all the new images ready to go. This is what I am struggling with.

The only option I see is when the new theme is ready, publish it, take the site down briefly and go through and update all of the product images.