Now remember, video you have is most likely temporally compressed with interlace motion, so you may not get the EXACT frame you want in high quality, but usually you can get one that is close (lacks any sort of motion issues).
Use an MPEG-capable version of VIRTUALDUB
, and then open the MPEG file. Drag the slider bar to the frame you want to grab, and then goto VIDEO and COPY FRAME TO CLIPBOARD.
Now open up your favorite image editing software (I suggest Photoshop 7 or higher) and then make a new blank file (size should be set automatic to the data seen on the clipboard) and then paste the image.
Now, video is low resolution, and has an aspect ratio that can stretch when viewed as square pixels. So you'll want to resize to 4:3 first in Photoshop. Most likely you'll have 352x480, 704x480 or 720x480 source. Resize to 640x480, and then crop off the overscan noise (if any) with the crop tool.
Now, if you want to make the image larger (to print), get the Photoshop 7 or higher plug-in GENUINE FRACTALS. I have GF Print Pro, the professional version. There are lesser versions available for less cost. This is where you upsize to print-worthy quality. It converts the image to fractals and resizes with a fractal method that looks far better than simple upsize methods found in Photoshop or other image software.
Another tool you may want to use if Neat Image, a professional photography filter that was created for dSLR cameras. It removes noise quite well. I'd run this prior to a fractal resize, if you use it.
You can safe to whatever format you want, JPEG, TIF, GIF, BMP, etc.
If you have motion video, interlace, and there is noise, one haphazard method you may want to try is to load the video clip into TMPGEnc Plus and then run an IVTC on a short clip (20 seconds, which includes the still you want) and see if the IVTC can eliminate the interlace frames and "restore" a film frame (or at least fake it, if the source was never film, sometimes it can do this). Be sure to pick the AUTO/ODD method, maybe try the AUTO/EVEN method too, see which looks best.
I realize this was all text, so it you need any pictures for anything specific, or links to any of the software discussed, then let me know.
I wrote a guide on cleaning and upsizing still images, with Photoshop and Genuine Fractals here: http://www.digitalfaq.com/dvdguides/...ases/lowresfix
I frequently use these methods for creating DVD case artwork when source images are in limited supply, or when screen grabs are needed for printing, for whatever reason (usually also DVD case artwork, sometimes menu artwork).