Sudden increase in aircraft size for EXTERNAL views

Forgive me if this question has already been asked and answered (I did search the forum but could not find anything relevant).

This is about the EXTERNAL views of the aircraft, i.e. Spot & Locked Spot.

Why is it that the exact same aircraft will sometimes appear "normal" i.e. scalable to your screen size and properly fit on the screen with all parts showing and with the ability to zoom in and out as required (using the '-' and '=' keys or scrolling the mouse wheel), and at other times suddenly appear so close and large that only a small component of the aircraft can fit on the screen and you can barely zoom out at all?

I am providing links to a couple of files to illustrate the issue..
PROPER SIZE.jpg - Shows the aircraft as it SHOULD appear.
http://www.daraious.com/FSX/proper-size.jpg

ENLARGED SIZE.jpg - Shows the extreme close up and enlarged view.
http://www.daraious.com/FSX/enlarged-size.jpg

I am sure others must have encountered this and I would love to know that there is a fix for this. Would really appreciate some help.

Thanks,

Daraious