Normally you will see a notification to load external images. These aren't loaded by default because they may form a security risk (such as tracking that you have read a message).

In the message window just see the green bar with this text:

'Remote content was hidden: show remote content - always show remote content from...'

And click the appropriate option.

On the emails I was asking about there is no message window with a green bar. I am familiar with that screen. There are no notifications or anything, just empty boxes where the image should be and a little icon in the upper left corner of the box.

Could you please check your settings with the privacy settings article?

Did everything the article suggest and just got an email where the pictures didn't show.

If you restart your computer in safe mode do the images display.

Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.