Hello,
I confirm that there isn't option like this, but you create override viewin order to custom this.
Note : Override aren't erased when you update your HikaShop Version.
To reach your override, and especially which process your add to cart button, follow this steps :
- Go to Components => HikaShop => Configuration
- On Display dropdown, select Views
- Use dropdown to find more easily your view, here quantity View like on screen below :
Note : For the red value, of course select your front end template, here on my example it's protostar
- Find
show_quantity, and edit the view to insert your image directly in the html with an span and a src="url/path/image"
Note : Later, if you want erased your override, click on the little trash icon.
For your second point, maybe I had bring some part of your response, the other part will come with views time and experience thanks to view and override system.
Hope this will help you.
Regards.