My site is www.eventtalentresources.com. I believe that I am using the most current WP as well as Atahualpa. As you will see, on my various pages I have text in columns.

I would like to have an image pop up when someone hovers their mouse over any of the text on the various items listed on the page.

I have attempted many solutions but none have worked thus far.

Can this be done via the Wordpress "add media" toolbar feature? OR, will I need to add custom CSS to the theme and include custom HTLM code for each hover image? Your thoughts are appreciated.

I would start searching for a plugin. Here is one possibility.