| 
	
		
		
		
		
		 
			
			Kindle devices do not extract cover thumbnail images from azw3 format. 
 
If you use calibre to sideload an azw3 book via USB it will create a thumbnail image with the proper name and format and put it into the correct location for it to show up on the Kindle. I don't believe that there is any way to do that using the web browser.
		 
		
	
		
		
		
		
		
		
		
		
		
		
	
	 |