It appears that the ViArt cart is automatically compressing my product image files after I upload them, ex. a 100kb file becomes a 23kb file on the live site. How can I turn this feature off? Image quality is very important for my products..

Have you tried 'JPEG Quality' option in the Products Settings on Images tab?

Hi Monk, yes I did - I left it at 100 and got compression and emptied the field entirely and still got compression - just a little less so.

One more think that you probably activated image resize option?
 
If you don't use it then most likely you need to contact support team