Is it possible to set a slider image + text without making a post? I just want to have a nice image and a short blurb talking about the website is about.
If you don’t want to use posts for the slider then you can use the pages for the slider as described in the following topic.
https://colorlibsupport.com/t/slider-for-pages/
The solutions posted in the above topic is for Sparkling theme so it won’t work for you if you are using Dazzling theme so to achieve this you have to develop custom solution. You can refer the solution posted on that topic to develop solution for Dazzling theme.
Second, the retina image fix didn’t work
Could you please tell me how you tried to fix it?