Website Banner for Desktop Showing Blurred on Dawn Theme

[izzy365]

I implemented some code for the dawn theme to show a different image for mobile.

Since adding this I've been having issues where the desktop banner is a low resolution.

I've tried following other articles and code but nothing seems to work.

It's like it's applying a smaller resolution to the image than the one uploaded. I've tried uploading multiple different image sizes, larger and smaller and the exact resolution but it always reduces it.

I think there must be something in the code shrinking it but I can't work out what it is.

Could anyone help?

This is the website: https://www.papersmiths.co.uk/

[DitalTek]

I don't know what is your expected resolution here, so how do you feel about image below? Is it you're expecting?

[izzy365]

The text / writing on the planner is going blurred when uploaded. Whereas on the original image it looks crisp and high res. Top one is the uploaded version. It seems to be fine for mobile and smaller browser windows, but when i open it on a larger desktop screen it doesn't look good enough quality.