Okay so the Webflow Designer is not a photo image engine or optimizer. It’s not like Photoshop or Affinity. The quality of your photo management occurs at the beginning. You’ll need to build a collection of photos that are used for your site, and open and edit them in a full image program. That’s where you’re going to get the color correction, toning, optimization, etc. When you start your collection each photo will need to be edited, optimized and exported individually. Save on your drive, then load into Webflow; you won’t have to do anything in the Designer, simply insert.
I would refrain from resizing, editing in WF; it’s built for this. Do all the work prior to uploading into your assets. If you need assistance or a video to show the best way to manage photos, I would be happy to create one for ya.