My Samsung Galaxy S III claims that a screenshot was "copied to clipboard". What? I'm used to the Palm Treo 700p, running Palm OS.  On Palm OS, the system  clipboard can hold only text.

I now also own a Samsung Galaxy S Relay, running Android "Jelly Bean" 4.1.2.  This is a phone rather similar to the Samsung Galaxy S III, but with a slide-out physical keyboard included.

I take screenshots in the usual way it's done on a Galaxy S Relay.  I hold the Power + Home keys at the same time for a few seconds until I see a white border around the edge of the screen.  (Not for too long.  I don't want my phone to suddenly power off without saving anything to disk.)

Now:


Like a Galaxy S III, my phone then saves a screenshot to a "Screenshots" photo album.
Like a Galaxy S III, my phone shows a notification labeled "Screenshot captured".  I can expand the notification using two fingers to see a preview of the top few centimeters of the screenshot, and then can tap "Delete" or "Share".
And, like a Galaxy S III, my phone displays a pop-up "toast" message at the bottom of the screen which says Copied to clipboard.


Hold on.  What?  The screenshot was copied to the clipboard?

Can the clipboard, in any version of Android, hold images?
The clipboard (like on Windows for instance) can hold different types of data.  

Raw images (like your screenshot) are one of those possible clipboard contents and thus you can paste them in, given that the app you use allows you to paste image data from your clipboard.

The supported data types that the clipboard can hold are mentioned in the Android Documentation (https://developer.android.com/reference/android/content/ClipDescription.html).
I believe it either saves an Intent with the type ACTION_ATTACH_DATA or a Uri to your image or holding your image as a data string (Base64 encoded).