I was able to find this page that solved the problem for me. Make sure to select “full size” from the drop down when you select your image to upload. I had to scroll down in order to find it, so it is easy to miss. Not sure why it doesn’t default to full size.
https://docs.themeisle.com/article/213-slider-images-showing-blurred
Same here. Images on the developer page look great, but everything we’ve uploaded is pixelated. Doesn’t matter what quality we start off with or whether we change the output width, etc.
