is the download capacity of your internet connection exceeded (momentarily) when you stream and simultaneously download those graphics?
This happens when testing it locally.
In considering kglad's comment about streaming capacity I starting running a brief test whereby the external graphics would be loaded into the flash file and attached using the attachMovie method rather than loaded using the loadMovie method. In doing so, I found the offending code.
The code was borrowed from a previous program that streamed a number of videos of different sizes. To make a long story short, for that project I was setting the video player visibility to false each time a new video loaded and this was done where the loader was given the loadMovie command. Visibility was turned on when the loader issued the onLoadComplete call. So I got exactly what I was asking for a momentary interruption in the visibility of the video.