The first step, after logging in, is to navigate to the page you want to edit and click the blue Manager icon: 
In the edit window, position your cursor at the spot where you'd like to insert the image and click the Insert/Edit Image icon: 
You should now see the following:
The pane on the left shows folders and files currently on the server, and the pane on the right shows any files in that directory. You may choose to organize images by creating appropriate folders before uploading.
Upload your image file by clicking the [ Browse ] button and [ Upload ] at the bottom of the window. When your image is uploaded, it will appear in the left panel and can be selected. When the filename appears on the box at bottom left, click [ INSERT ] button.
You should see the following:
Enter text for the image description. This is important as this text displays if the image is not visible for any reason (text only browser).
On the appearance tab, there are options for changing the dimensions. This does not make the images smaller and faster to download - it only resizes it on the screen. Be sure to leave the Constrain Proportions checkmark checked as this will keep the image from being distorted.
In order to allow text to flow around an image in a document, the image Alignment must be set to "right" or "left". Adding Vertical or Horizontal Space will keep the text from coming right up to the image.
Finally, to prevent an unsightly blue border from appearing around images that contain links, specify a border of zero.