Product Images & Slide Bar Issues on Mobile Phone

[ShoreSeekers]

Hi Shopify friends, hoping someone can kindly help me out. I'm having issues with my product images when viewing these sections from my mobile phone. When working on mobile view on my laptop the sections appear to be somewhat okay but not perfect. Although when I view the products via my mobile phone the images are massively inflated and although very hard to control the slide bar, making it impossible to navigate around or effectively view the images properly. 

Is there a way around this issue? Website link: www.shoreseekers.co.uk

Examples of my website on laptop desktop:

Examples of website when viewed from my physical phone:

[ShoreSeekers]

Thanks for the feedback - Can you kindly recommend a suitable image size?