Hi @cometto,
Sorry for the delay in getting back to you. Most of the files listed in the Google Page Speed are original images, however, I could also notice there are thumbnails listed too.
By default the free version of Smush will only optimize thumbnails, ie, for eg, suppose the image file name is abc.jpg, then it would be the original image. And abc-100×100.jpg, abc-500×500.jpg etc would be the thumbnails of abc.jpg.
Since WordPress by default uses thumbnails Smush only optimizes the thumbnails images, however, if there are plugins or themes that use original images then such images would be listed in PSI scan result.
That would be one case, regarding other existing thumbnails listed in PSI result would be due to many factors.
Smush uses Lossless Compression so it should be optimizing the image, however, depending upon the images it can sometimes not be adequate and there could be further compression that could be performed.
Could you please check whether the image size is the same before and after the image was optimized? This would give a better idea if images were actually smushed or whether there is any conflict.
What can I do to restore everything to the beginning?
You could use a plugin like Regenerate Thumbnails which should help to restore the images:
https://www.ads-software.com/plugins/regenerate-thumbnails/
Please do make Smush is deactivated and you have a backup of your website before running the above plugin.
Kind Regards,
Nithin
