How can I tell if images are being automatically optimized?

Thanks for reporting this. We will think about a way to mark optimized images. Meanwhile, you can check the plugin’s image optimization tab. If you get the message that all images are optimized, you can trust it ??

This feature would be very useful to me. My images are already optimized from another service. Re-optimizing them makes me nervous because it will replace all my images. I only want this plugin to optimize newly added images. But there’s no way for me to see this happening in my situation.