This workflow watches a selected Google Drive folder for any images added to it.
It then takes that image, sends it the the tinypng.com service which optimises and reduces its size (where possible)
Tinypng then returns the updated image which is then automatically saved in your chose Google Drive folder
Setting things up
It's pretty simple to configure and should only take around 5-10mins.
You only need to set up credentials for Google Drive and Tinypng.com
For Tinypng.com you can sign up for their free tier API access which gives you 500 optimisations per month
Once you have those two things, you just need choose your 'input' folder to watch for images and your 'output' folder for where these images should be stored
There are a few more optional things you can do such as the naming of your final image and also lots more you could do with the Tinypng API for more advanced image optimisation