Just use the upload button in the cPanel file manager and locate a picture, by clicking the browse button. It's exactly the same as uploading a web page.
Then, to add it to a webpage (or embed it, as you should say), use this html code where you want it to appear, replacung images/image.jpg with the path to your image and caption with a brief caption:
Code:
<img alt="caption" src="images/image.jpg" />
-Luke.