I appreciate that you have let us know which theme you are using as that is helpful. Looking into the options available using theBlockshop theme, I would suggest attempting to resize the images with dimensions from 1024 x 1024px to see if that no longer cuts off the images on the mobile version of the theme. While I was looking into this, I noticed that the Blockshop theme isdesigned and supported byTroop Themes.
Since we are a bit unfamiliar with the style of coding that is used, it would be best to direct this inquiry to the developers of the theme. They should be able to assist you with additional support to this inquiry. I did come across theirImage size guideas it explains which sizes for the images should be used. I came across theirContact Us pageand wanted to provide it to you.
Let me know if you have any additional questions.
Ollie | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog