FFShare app
FFShare is System tool that is open source under the GPL-3.0-only license. FFShare pipes image, video and audio files through ffmpeg before you share them.Doing so reduces the file size and also has the added benefit of stripping all metadata that may be attached to those files.
To do this this just share your videos or images and choose FFShare. The app will open showing the compression progress and when its done a new share dialog will reappear with the new compressed video or image.
Source Code
This app is open source and hosted on GitHub. A star would be greatly appreciated.
https://github.com/caydey/ffshare