Slideshow images pixelated on mobile (Refresh Theme)

[jelt]

Hi, I'm having an issue where my slideshow images look perfect on desktop but they look extremely pixelated on mobile. I have checked in multiple different mobile devices and they all have the same problem. 

Can somebody help me solve this issue please?

My store is https://jeltapp.com/

Thanks in advance. I have seen no responses to this particular issue anywhere else so any help would be greatly appreciated.