Depends on what software you use. I do it all the time in Power Director 12 but I've never done it in GP Studios but did a quick search and found some info (see below).
In PD12 you just find the frame you want to save and click the camera icon. This in turn puts the frame photo into the clips section of your current video. Then all you is drag it to the timeline.
The following is taken from the GoPro website
You can easily export a still image from your video file using GoPro Studio. Here is a procedure that details the process:
1. Go to Step 2: Edit
2. Select the desired video clip so that it is displayed in the Player window.
3. Mac instructions - Place the playhead so that the frame you want to export is displayed in the player window, then selecting Share > Export Still.
4. Windows Instructions - Place the playhead so that the frame you want to export is displayed in the player window, then selecting File > Export > Still Image.
5. Then just select the image Name, Location and Size to Export (small, medium, large, & native) and click Export.
6. Check out the location you specified to verify that the image was created.