HTTP to HTTPS – Incomplete Encryption

Hi,

I recently changed the site from HTTP to HTTPS, and some files images are still using HTTP.

I noticed that the insecure images are WP-generated thumbnails. Should I just use a plugin to regenerate them?

The other insecure resources are fonts, e.g.
http://fonts.googleapis.com/css?family=Open+Sans:400,800,300,700

How would I set the fonts’ URLs to HTTPS?

Thanks!