lcmweb,
Before answering your question, the very first things I would do are to install an updated editor for your Joomla installation, Art of Editor is good and free:
extensions.joomla.org/extensions/edition/editors
And this is the one I would use:
www.theartofjoomla.com/extensions/artof-
editor.html
This will allow you to easily upload images into modules "on the fly". It will improve your content editing experience all-round.
After downloading this install it via Extensions Install/Uninstall.
Then visit your Global Configuration area in Joomla admin and select this editor as default.
Now to get images into your sidebars, go to Extensions > Module Manager
Create a new module with the Green Plus button top right, choose "Custom HTML" as your module type.
Now you should have a module you can enter custom text and/or images into and then publish either right or left.
Let me know how you get on with this, happy to give more detail or take a look at your site if needed.