We have created two different images from same viewpoint with the below mentioned option and found that there is a difference between two images. Mainly some portion of the image is not shown (occouring zoom effect in the images) in Option 2 as it will shown in Option 1 whereas the image size and camera angle is same for both the files.
Images export option
Option 1
Export > Images & Animations>Image
Option 2
Export > Images & Animations>Rendered Image
Here we have attached the two screenshot for your reference.
I tried to reproduce this but so far have been unable to:
Rendered Image
Image (Presenter)
Image (Viewport)
Image (Autodesk)
This is Navisworks Manage 2013 SP2, with Explicit 256x256 setings. Can you reproduce this with any file? What version of Navisworks are you running? What are the image settings?