There are two ways you can do that. The simplest is to create a launch button to run your desired transaction code, and then add your image as a custom icon and associate it with the launch button. Use the "Upload Icon" tab of the "Add icon" pop-up for the button,
You can also add the image to your flavor as an image object and then use its "PushOnClick" property to associate it with a script button. That script button will have a script that runs the transaction. This is more flexible as it allows you to automate some aspects of the target transaction - fill in default values in the initial screen, or even skip it altogether if appropriate. It is a little more fiddly, though.
To do this, you need to pop up the "properties" pane, like this:
First look at the properties for the script button and grab its id - the "Personas/..." at the top. Clicking once at that text will copy it to the clipboards. Then look at the properties of the image and scroll down to the bottom, and paste the button's id in the "PushOnClick" field as above.
Steve.