Thank you for your message, I would be happy to offer you some suggestions for this moving forward.
I would love to hear more about your idea, is it simply for aesthetic design or do you think it would benefit your customers more to have these images larger? Either way, it may be simpler to reach out to our Themes team to see if they can help you customize this rather than playing with different code on your end! If are eligible for design time and would like to see if our themes team could help out with this, please visit our Help Center here and log in to your account to create a support request. Once you reach a live support member and explain your idea, they will be able to check with our themes team if this is a customization you are eligible for.
You did mention already trying some coding to achieve this. Just a friendly reminder that if you still have customized coding in your shop, our themes team would not be able to support this. If that is the case, you could always hire a Shopify Expert to help you out with this customization.
I hope some of these ideas get you on the right track, feel free to reach back out here with any questions you may have!