Thank you for replying. In PowerDVD9, you could go into the settings and on the Player tab you would click the "Advanced" button, then the Capture tab. There you could set the "Capture aspect ratio" ("current video window size" is one of the options). Selecting that, the screen capture image would be the same size as what you are viewing. If you're viewing in full screen mode, the image comes out full screen size.
In version 14, the only capture options (now called "Snapshot") are the Snapshot format (.jpg, .bmp or .png) and the directory where screen captures are saved. The snapshot comes out the size of the original, non-fullscreen video regardless of the size you are viewing the video in.
I tried .jpg, .bmp and .png file formats, and high definition and standard definition videos. Nothing made a difference.
Properties of one .jpg capture:
Dimensions: 640x480 pixels
Resolution: 96dpi
Bit depth: 24
Programs used to view image: IrfanView, MS Office Picture Manager, Windows Photo Viewer, even tried PowerDVD 14 (doesn't matter what program, the image is the size it is).