This is definitely possible. From looking at your source code I’m going to assume you have a snippet called product-grid-item or something similar. This is the snippet that holds the code for the product tiles on your collection pages. Inside that snippet, look for the figure element with a class of productitem–image. Inside this element you’ll want to add some logic to determine what product image to show.
Two simple options would be to make use of the image alt text or the image file name to specify whether the image is a male or female. Then in your liquid you can check if the collection handle contains ‘womens’ or ‘mens’ (in that order because ‘womens’ also contains ‘mens’). If you’re in a mens or womens collection, you can then loop over the product images and check the file name or alt text for “male” or “female” and use that image. If the collection is not mens or womens, show the product featured image as it does now.
Alternatively, to optimize this, you could update all unisex products so that the male image is first, and the female image is the 2nd image. Then instead of adding male or female to the alt text or file name, you could just output product.featured_image for the male photo and product.images[1] (the 2nd product photo) for female.
Happy to write out a more specific example if you can provide your code.