video pictures

[John Obrien x4089]

I tried to post this before but I guess it got lost.  How does one
enter video pictures into the UNIX-pc?  I have the pictures demo from
the STORE! but have no idea how to enter and or manipulate my own.
My inclination is that they would come through the RS232 port from
a CAMCorder or similar device, is this true?  I don't need detailed
directions but would like to be steered towards some source of knowledge
about how to do this.