First add the 'Crop tool' item to your page, by clicking 'Insert' –> 'Image' and then 'Library' which will launch 'File Manager'. In the 'Image tools' folder of the 'Library' choose the 'Crop tool' item before clicking 'Use this'. Alternatively, you can choose the 'Files' icon (in 'basic view') or the 'File Manager' icon (advanced view) and both will launch the File Manager. You can then navigate to the 'Crop tools' folder within the 'Library' and then locate 'Crop tools (polaroid)' which you should highlight, before clicking the 'Use this' button.
You can now close the 'File Manager' and move the 'Crop tool' by clicking on it once and then dragging it to the correct position.
Once positioned and resized you can then double-click the item to start editing it with the Sitemaker Editor. Select the 'Style' tab on the 'Editor' which will allow you to browse for and select your image file or files.
Once you have chosen your image, select the effect you desire i.e. border style, transparency. You can then resize and reposition your image on the page to get it exactly where you want it.
Remember to save your page when you have completed your changes.