This is accomplished using the JCE plugin: mediabox.
For more info: www.joomlacontenteditor.net/support/tutorials/jcemediabox/266-create-an-image-popup
1. Preparation: Have both images uploaded--the thumbnail and the larger image.
2. Add the thumbnail image to the article or module, per usual.
3. Go get the relative address of the larger image (relative means /images/whatever/yourphoto.jpg -- do not include the domain name in the url). You can use the normal image edit/upload function to go find and get the url for the appropriate image.
4. Click on the thumbnail image in the article using the AdvLink 
icon. On the Link tab, enter the copied relative URL of the larger image. Click on the Advanced tab. From the class list, select "jcepopup."
5. OPTIONALLY, if you have MULTIPLE IMAGES that you want the user to be able to page through on the larger photos (obviously, they need to be in the same article), you can do the following to GROUP photos together:
a) On the Advanced tab of the AdvLink function, click on the first Relationship pull-down: Relationship page to target. At the bottom of the select list, click "Add Value" and enter some appropriate group name. Enter that same group name for all images that you want the user to be able to page through.
You can see the example in the more info link: www.joomlacontenteditor.net/support/tutorials/jcemediabox/266-create-an-image-popup
The WomenTech Educators Training got us thinking intentionally about who we were going to target for outreach, how we were going to target them, and how we would follow up to make sure we had actual results linked to the different programs and events that we were holding. Since then, it has grown organically and blossomed into something that our college just does naturally.
I think getting together as a team with intention—because we're all so busy—and developing a written plan that we could stick to was what made all the difference. I don’t think we would have ever done that if it wasn't for the WomenTech Educators Training.