I am using the latest version of Dawn Theme and I have noticed that on mobile version only, some product images have extra white space compared to other product images.
The problem was also there with the first version of Dawn 4.0.
On desktop version the problem does not occur.
I have checked the images size and they are all the same.
I appreciate that you have included your online store URL as well as screenshots of the space you are referring to! Based on Human Factor International’s research, white space helps increase the comprehension factor by nearly 20%. Added white space gives emphasis to your call to action buttons and key information. It lets your visitors breathe and appreciate the website better since things are laid out well and easy to spot. A great article for reference on this research is Why whitespace is so important in web design.
Looking into the Dawn theme, I noticed that there is not a method of reducing the spacing/padding on the product pages using the Theme Editor. However, it would be possible to make a custom coding change to the theme to have the space reduced. Since the Dawn theme is designed and supported by Shopify, we can use free design time for Shopify themes to have our internal team make the changes on your behalf.
If you are interested in using the design time, you will need to login to your store using our Contact Us page. This will allow us to securely verify you as the store owner before discussing the changes you would like to see on your online store.