The best privacy is not to publish images of kids online at all. You can focus on what they are doing rather than who is doing it. This can be achieved of taking photos from behind or showing mainly hands doing something.
But sometimes you can't really avoid having faces in pictures and this is when Anonymizer shines. Anonymizer uses face detection and automatically hides faces by blurring them or covering them with a solid color or emoji.
You can also draw a custom region that you'd like to hide.
Automatically find and blur faces with face detection.
You can also draw a custom sections you want to obfuscate.
You can use different ways and shapes to hide faces, like blur, solid color or emojis.