How to Find and Use Amazing Science Images in Class

I have been seeing so many amazing science related images lately. I have started collecting some of them here.
They are amazing, eye catching, and engaging. But how can I use them in class?! That's been a his question bothering me on and off recently.

Here is a list I've come up with, and I'd love if you'd add your ideas:

• Print and hang them up like posters
• Have students explain the image at the end of a unit  That works especially well for a photo like this from http://www.verycoolphotoblog.com
  http://www.verycoolphotoblog.com/2012/12/03/star-trails-at-little-sahara-dunes-in-utah/
• Use them for engagement at the start of a unit
  
• Use them as a writing activity on inference (thanks sciencenotebooking.blogspot.com)
• Use them as a free write/prior knowledge -- what do they think is going on? -- this could be science related RTI, a few minutes left at the end of class, or simply for interest and engagement.  Remember why you think science is cool!!  Share that with the kids and get them excited about science! 
• Maybe have them use the images to create images of their own (photos? Cartoons? Joint project with the art teacher?)
• Create interest for a project that is coming up (example - animal photos, or adaptations, cool weathering formations).  Do a gallery walk or powerpoint to get them thinking. 

How would or do you use really cool science images in class?  Or do you just like to look at them?