Upgraded to Xen 2.3 last evening, and since the update, users have been unable to upload (or view) images. They can view OLD images (uploaded prior to the update), but when you try to post new images this is what you see:
If you click any of the image links, XenForo generates this error message:
I am using Imagemagick PECL - same as I've been using for years. As I mentioned - this is only happening with new uploads - all the old uploads (prior to last night's upgrade) work fine.
Actually - you put me on the correct path. I had not enabled XenForo image optimization, but I had been using a 3rd party image optimization add-on that it appears does not work with 2.3.