I record a Photoshop action to save file as png format. It works except one thing: file sizes differ when I do manually save and when I play the save action (recorded exactly the same steps in manual save). For example, in manual save the file size is 10KB, in action save it becomes 40KB.
I tried several different files and got similar results. Action save always increases file size by around 20-30KB, which matters to me since I am doing iOS dev and keeping file sizes minimum is essential.
Any idea what cause the file size difference, and more importantly, how to get rid of it?