This answer will explain how to use the Instantsite Editor toolbar to insert images into web pages.
Click on the location where you want to insert a picture.
Click Insert/Modify Image (the yellow box with the picture). The Image Properties dialog box will open.
Click on the Browse Server button to identify the image you wish to insert.
This will open the File Upload window. If you have already uploaded images, then they will be available here, just click on the image title to insert it into your page. Otherwise, click the Choose File button to upload a new image.
This will take you back to the Image Properties window. Here you can customise your image. For example, you can add Alternate Text (Alt tags), align the image on the page, and add horizontal and vertical spacing.
You can also use the tabs at the top of the window to add a hyperlink to the image, and to access the Advanced Settings. Once you are happy with your image settings, click the OK button.
Your image will now be displayed on your page. If you wish to edit it, right click on the images and select Image Properties.