Images dragged or copied from Safari windows appear upside down.
For best results, change the display to millions of colors. (The issue may still occur infrequently in millions of colors.)
 
-  From the Apple menu, choose System Preferences.
-  From the View menu, choose Displays.
-  Locate the Colors pop-up menu item on the upper right.
-  Choose Millions from the pop-up menu. 
-  Quit System Preferences. 
-  Quit and reopen Safari.