523 images and 2,660 thumbnails are not yet optimized by ShortPixel.

After doing two Bulk Image Optimizations, I have a ton of images which have not been optimized and supposedly have errors in them. What type of errors might that be and why can’t they be optimized?

A couple examples:
https://www.jacksworld.org/wp-content/uploads/2015/04/santahat.jpg
https://www.jacksworld.org/wp-content/uploads/2015/04/snowcreek.jpg
https://www.jacksworld.org/wp-content/uploads/2015/04/ViewScreen-Jacks-World-1024×768.png

My Site: jacksworld.org

Let me know if you need anymore info. I really love the plugin, and have already purchased an upgrade for more images so I hope we can figure this out.

Thanks for your time,
Eric

https://www.ads-software.com/plugins/shortpixel-image-optimiser/