While I believe that users do have their ways to put good screenshots from videos (trailers, etc.), I've noticed that some others have the tendency to simply use the print screen function to take images from the video player. This usually results in loss of quality and resolution, especially if your computer's screen has a display resolution smaller than 1920x1080 pixels. The quality loss is also a problem if you take a screenshot that is smaller in resolution than your display screen, e.g. Find Makarov: Operation Kingfish, which is only available in HD (1280x720 px). So here's some tips for those who are not familiar with taking good video screenshots:
- Download the video in high-res (in most cases FULL HD, 1920x1080, if available of course) by using an appropriate software (such as Free YouTube Downloader). Note that if the video is available in a resolution that is even higher than Full HD, feel free to get the best.
- Use a video player that can capture snapshots (such as VLC media player, which has the "Take Snapshot" function), take screenshot(s) at at your chosen timecode(s) and locate the image(s). The screencaps are in full resolution, regardless of your computer's display resolution.
- It depends on the situation whether the images should be cropped or not (e.g. for trailers it is usually not advised). For showing some specific elements (such as menu icons for weapons, etc.), cropping should indeed be fine.