Hi Jared
You can probably do it right from the RoboHelp HTML UI.
Give this a try. Click Tools > Options > Tool
Locations.
Click the Add button and add the image extension. (You may
have to do this as many as three times if you are choosing the
editor for .GIF, .JPG and .PNG images)
Add the extension and the path and file name of the image
editor. For example, I have .PNG in mine and the three fields have
these values:
File Extension: PNG
Editing with: D:\Program Files\TechSmith\SnagIt
8\SnagIt32.exe
Viewing with: D:\Program Files\TechSmith\SnagIt
8\SnagIt32.exe
Cheers... Rick