On Mac, you can export still images from videos or movies using the system apps, without the need for third-party video or image editors. QuickTime Player, the default movie player for Mac, allows users to directly copy the current frame to clipboard so they can paste it to other apps. Check out this tutorial to export still frames from a video using QuickTime Player on Mac.
Today, we will use iMovie, a preinstalled video editing application on Mac, to grab still photos from movies or video files.
Save images from video in iMovie’s media browser
At the upper left section, you can find all those imported source media files using the media browser. Skim a clip until you reach the frame you want to save. Then click the Share button at the top right corner, choose Save Current Frame. The Save dialog appears where you can choose a different file name and/or location, finally hit the Save button to export the selected frame as JPEG image to your Mac.
Export a frame from video in iMovie’s Timeline
Move the playhead in the Timeline to find the frame you like to export, then click the Share button at the top right corner, choose Save Current Frame. Optionally give the frame a different name and choose a location for you save it to your computer in JPEG format.
Grab frames from video in QuickTime Player
Open a video in QuickTime Player, find the frame you’d like to grab, then go to Edit > Copy to copy the select video frame to clipboard. or press the keyboard shortcut Command-C to copy that frame. After that go to paste it into Preview or any other app that handles images. More details can be found from the linked page in the first paragraph above.