Converting Video to Frames

I'm trying to convert a Photoshop video file into frames so I can edit manually to reduce the file size. When I go to do that in the timeline and choose "Convert to Frame Animation" it just converts the entire video into 1 frame. Any idea how to convert the video into actual frames?

Note: I'm ultimately trying to save the file as an animated GIF but when I do it via "video", it's too large.