Squarespace CSS for Variable Image Dimensions

I run an artist's cooperative gallery on Squarespace Commerce and our shop automatically crops every product photo into a fixed aspect ratio. Because our items are fine-art prints that come in many different aspect ratios, the forced cropping ruins the composition and confuses buyers about sizing.

All I need is a concise Custom CSS snippet (plus any tiny tweak to site-wide style settings if required) that:

• lets each product image—both in the main shop grid and on individual product pages—render in its native dimensions rather than being forced into a square or any other preset ratio
• keeps the layout looking tidy on desktop, tablet, and mobile breakpoints

I’m not comfortable pasting code into Squarespace’s Custom CSS panel.

Deliverable: a short block of tested CSS inserted into the website.