Many times when I receive an email containing pictures (not as attachments), I only can see a square box with a red X in it. Is there a way to correct this problem? It does not happen all the time.

The person apparently sent you a picture format that your browser doesn't know how to show.

To fix this, you need to find out what kind of picture this is to install the plugin for this format.

If you find the plugin is already there, maybe the email is actually in html format. If this is the case, the html is calling for an image that isn't on the web. To find out select "view source" and look at the code. If it has code like this:
<IMG src="/NPI-Logo.gif"
The link won't work for you because the directory NPI-Logo.gif isn't on your computer.

To fix this on the sender side, change the code to something like this before sending:
<IMG src="www.website/NPI-Logo.gif"

Hope this helps!

My guess is that your mail client is not configured to receive HTML mail format. Maybe you can try playing arount with the settings.