- Fine directional texture (the weave of the hat, hair)
- Fine non-directed texture (the feathers)
- Fine detail (eye glint, lashes)
- Medium texture (reflected hair)
- Sharp edges
- Curved edges (mirror frame, shoulder)
- Smooth gradients (skin, blurred beams on left)
- A closeup face
- Color
- Strong contrasts
I'd love to see a consensus around a good alternative high-resolution test image that has a bit of all of that (and maybe with a Macbeth chart thrown in somewhere too) with appropriate licensing, but none of the suggested alternatives (e.g., cameraman, mandrill) that I've seen quite have everything or are of any better resolution.
One source that I have recently been using for test images for my experiments, though, is the Wikimedia Commons Picture of the Year finalists collection: https://commons.wikimedia.org/wiki/Commons:Picture_of_the_Ye...