The root of this issue is usually because a plugin/theme is auto-generating image sizes, and checking for the wrong file with mismatched dimensions. This causes EWWW IO to re-optimize the image (since the filesize is different and the “new” image is un-optimized).
To figure out where it comes from:
First of all, you turn on EWWW IO’s debugging option. It’s over on the Support tab of the settings, and once you have it enabled, you wait. Just do nothing, and the normal traffic of your site will typically trigger the image regeneration, and when debugging is enabled, EWWW IO also keeps a record of how/why every image was optimized.
Do not reset the counters during this process, or the data in this next step will be harder to find…
After 3-4 hours, look under Tools->EWWW Image Optimizer (or wait until the notice shows up again). At the bottom of that page is a button to Show Re-optimized Images. Click on that, and you will be able to see trace logs for every image that has been optimized since debugging was enabled. If you’re not familiar with PHP or trace logs, just copy and paste as much as you can, and send it to us and we’ll work out where the bug is.
If you’re concerned about the security implications of the trace logs, you can redact some of the path information, or send it in via https://ewww.io/contact-us/
