I believe this may be caused due to your personal settings. Go to Settings > My Settings > Account Settings > Webmail tab. You'll see an option for Display Format. Change the dropdown menu from Text to HTML and save.
I tested this on my end, using 13.2, and it worked as expected. When I have HTML chosen, I see the inline images in the email body and as an attachment. When I change it to Text, the image is stripped out of the body and only shown as an attachment. Please test this out and let me know what you find.