Hi
I was so surprised when I saw that I could not do this, but adding a pic of your character to their character sheet would be very useful to me, so I remember who is who. I did find an alternative to add an image, but it only opened a window allowing me to import from a scanner or camera, but all my pics are .jpg on my hard drive. 
Small thing, but it would make life a little bit easier. other then that, the program has been like a dream. 
Hi avihenda,
I’m sorry you’re having trouble with this! To insert an image into a text document, you can just drag the .jpg straight from your desktop or Finder, or you can choose Edit>Insert>Image from File… when the focus is in the editor and then navigate to where your pictures are stored and select them individually that way.
Glad you’re otherwise enjoying Scrivener!
(By the way, if you haven’t had a chance yet, I definitely recommend going through the Interactive Tutorial, in the Help menu. It covers a lot of Scrivener’s features, including different ways to add images to your project.)
You can also drag an image into the synopsis area (if you’re using the Character Sheet in the novel template then there’s a placeholder image that you can replace by dragging an image onto it).