How do you base-64 encode a PNG image for use in a data-uri in a CSS file?

Question

I want to base-64 encode a PNG file, to include it in a data:url in my stylesheet. How can I do that?

I’m on a Mac, so something on the Unix command line would work

Answer 1

This should do it in Python:

import base64
encoded = base64.b64encode(open("filename.png", "rb").read())