I observed this on Chrome 52.0.2743.57 on my Chromebook Pixel (HiDPI).

Steps:
  1. Load the following image: http://i.imgur.com/0NXELo1.jpg
  2. Observe the default zoom level

What's supposed to happen is the image is zoomed to full window size normally with a magnifying glass cursor icon that when clicked zooms it to actual size.

Instead, what I observed is that it was zoomed to 2x window size. Manually changing Chrome's zoom level to 50% made it work as expected.

oshima: I'm not sure if you're the right owner for this, so please re-assign if there's a better person to own this.