Sorry, I still do not understand how you are selecting the size, and the images selected are by their name the 179px version like
//bellaann.com/wp-content/uploads/2021/12/bad-bella-large-parfait-altered-1-179×179.jpg
For the box shadow, are you sure that in the slider options page in the section “slider Options” > Background Borders you did noy forget to put 0 in the px box? Because the default if box is empty is 5px
You probably also need to check the box “hide the border shadow around the Slider below the px box