After installing Image Optimizer, you can do the following tests to see if your images are optimizing correctly. 

Solution #1: Check from Magento backend

  1. Go to Extendware -> System -> Logs -> Logs and look in ewimageopt.log. This will list all optimized files and their before / after time. You need to download it to view more than the last 100.
  2. If there is no log file, then ensure the cronjob is running. Look in Extendware -> System -> Cronjobs and see if jobs have recently executed. If jobs have executed recently, then wait for the image optimization job to execute (it could take a few hours).
  3. (Option 2) If there is no log file, go to Extendware -> Manage Extensions -> Image Optimization and click “Optimize Images” button. This will begin to optimize the images. Depending on web server time out settings this may shortly stop optimizing after pressing the button, so keep an eye on the process.

Solution #2: Check with google PageSpeed insights

  1. Go to https://developers.google.com/speed/pagespeed/insights/ and input the URL of your store.
  2. Look to see if it says Image Optimization and click “See how to fix”.
  3. Any image inside a /extendware/ewimageopt/ directory will be optimized. Images in other directories will only optimize if they add the directory to Image Optimation -> Configure -> Custom Directories
  4. If Google says the image needs to be “Compressed and Resize” then the image is probably already optimized. It is in the list and will show as "bad" because the dimensions of the image (the width / height) are larger than the image is being shown on the store. That means your store images are using the width / height attributes of the img tag in an attempt to make the image smaller. You need to show your images at the correct dimensions or else Google will list it as bad. 
  5. If the images are optimizing and it shows it in the log and Google says they still need to be compressed, then you will need to install gifsicle, jpegoptim, and opting on your server and not use the online API. That is the only way to get Google to say you are good. Before going to that length, you can look at your log and decide if they are happy with the image optimization savings the online API is providing you and leave everything as it is.