This feature allows you to upload and use images that are saved on your computer. When editing the content of a form you will come across this toolbar that contains an "Image" Button.

Clicking the Image button will lead you to the Image Properties window.

Clicking on "Browse Server" will lead you to the File Manager where you will upload your image. 

From here you can click "Add file" and can either browse to or drag the image you wish to select in the box.

After the Image is uploaded to the File Manager, you will still need to Select it and click OK.

The text field "URL" should have a filepath / url in the field that links up with your image. Click the green "OK" button and you're finished!