I've never tried to grab a single frame from a video before - it must be simple, but not sure how to do it. The video is ProRes 2.5k from a BMCC.

I need one full resolution still to be used on a flyer for an orchestra's next performance. Need to do it in either/both Edius 7 or Vegas 12

In Vegas, create a project (even a temporary one) with the same resolution as the file, drag the file to a video track, place your timeline cursor over the single frame you want to grab, and click on the icon of a diskette at the right end of the various icons located above the preview window, and Vegas will save the frame a JPEG or PNG file (your choice).

Just make sure your preview quality is set to Best (Full).

What he said.

I believe the project size determines the size of the frame grab.

Attached a pic with the diskette button circled.

Thanks much