Vegas user for 5 years, but I didn't know this . . .
Still caps from the Vegas timeline are dependent upon project resolution.
I was compositing some 1965x1440 resolution photos (removing area-specific interlace flutter) with cookie cutter and gaussian blur on two tracks. I wanted to combine as a single .png file.
Still caps in a 720x480 project result in 655x480 stills. Changing project resolution to 1965x1440 resulted in still caps of 1965x1440.
Now, I can pan/crop and not loose resolution!
Cheers,
XOG