Hello,
Assuming you are using the Viewer control you can use the viewer.images property which returns an image collection that has MoveFirst, MoveNext, etc methods for navigating thru the images/pages in the viewer collection. You can use the viewer.images.currentImage property to get access to the current image and pass that to a RotateCommandobject that you have created and then assigned the rotated image back to the CurrentImage property.
There are C# and VB.Net ImageManSample solutions installed with ImageMan that show you the code used for rotations and navigating thru the images in the viewer.
If you have a Thumbnail viewer control linked to a Viewer control then you just need to delete an image from viewer.images collection and the Thumbnail viewer control will be updated automatically.