dsecareanu

I’ve installed the plugin on other sites as well, and there it optimizes all images.

This particular site has some old content issues that most probably generate these weird messages, but somehow both plugins identify a similar number of images with problems.

This is what your plugin tells me:
16973 images in the Media Library have been selected (15105 unoptimized), with 6815 resizes (0 unoptimized).
Previously optimized images will be skipped by default.

After running the bulk optimization several times it keeps telling me that those images are already optimized:
Full size – No savings – Previously Optimized

This is what Image Cleanup tells me:
Invalid Attachment Meta (14954)

I assumed that these are the same un-referenced images that your plugin doesn’t want to optimize for some reason (although, all of them are in the /uploads/ folder).

That’s why my suggestion was to look at these images and try to optimize them as well, even if they are not linked with posts in the database or are theme size versions of the same image.

Indeed, the advanced settings do provide you this option, but the message provided with the default settings on doesn’t say anything to justify those un-optimized images, hence my suggestion in the opening post.

Even with that option enabled, the message on the bulk optimization page remains the same as mentioned above.

When I mentioned hints I was thinking on the lines of:
– this plugin works well with Imsanity (to ensure images are resized upon upload) and Image Cleanup (to make sure no leftovers are clogging your site, generating bogus information in Ewww Image Optimizer).