Hello,
The images are not customized with Custom CSS Code due to their nature. Your images differ in size considerably. The only way to make the view awesome is to upload images of the same size and proportion.
WooCommerce Allows some settings that you can find under Appearance >> Customize >> WooCommerce >> Product Images.
You can define the “height” of the shop thumbnails by setting up the width:height aspect ratio in the “Thumbnail cropping” section:
Custom: In Custom you can select the aspect ratio of the image. Here are some of the popular aspect ratios (1:1, 5:4, 4:3, 3:2, 16:9 and 3:1).
Uncropped: Height of the image will be untouched. Images will display using the aspect ratio in which they were uploaded.
https://ibb.co/6mR6DbD
Best Regards,