The ImageViewer can be used to view a single image. The image is changed simply by setting the Image property to a new AtalaImage. It does not carry the benefits of the Workspace such as a built in image handler, however it has all the UI elements such as auto zoom settings, rubberbanding ability, magnifier, and other mouse tools.
The WorkspaceViewer derives from the ImageViewer and adds the functionality of the Workspace. It is generally much easier to use the WorkspaceViewer as you can open an image with myWorkspaceViewer.Open, apply commands, and make changes without worrying about handling or disposing the AtalaImage objects. There is virtually no additional overhead with using the WorkspaceViewer over the ImageViewer as long as the Undo Levels are 0 (which is try by default).
If you're not sure which to use, just use the WorkspaceViewer.
Original Article:
Q10034 - INFO: Should I use the ImageViewer, or WorkspaceViewer?