"An error occurred in the upload. Please try again later" EWWW Image Optimize

Please provide a screenshot of the error page. Also enable EWWW’s debugging option, and post the resulting output from the bottom of the settings screen.

https://www.filedropper.com/ewwwimageoptimizer1
https://www.filedropper.com/debug1

Based on your settings, and the fact that the image being uploaded was a JPG, I’m going to say it is probably due to the fact that WordPress is trying to generate 14 resize versions per upload, and your server is cutting off the connection too early (some hosts timeout at 30 seconds).

Your php limit is already 300 seconds, so that tells me it is probably upstream in the webserver config (apache, lighttpd, nginx, or other). If you have full access to the server, you can probably fix that, otherwise there are only a couple things you can do:

1. Try to disable a few of those resizes to get the time down.
2. Turn off automatic optimization, and then enabled scheduled optimization, and the include media library option.

The next version of EWWW is going to have a deferred optimization option to replace that use case, but that’s a long ways out yet (just started on it today).

Hello, thank you for answer. Could you, please, explain your 1 and 2 points, i. e. where and how could we disable few of those resizes to get them down?
And where should we turn off automatic optimization and then enable scheduled optimization, and the include media library option (what and how to include in media library?)?
And there is another very important question (as you mentioned -“it is probably due to the fact that WordPress is trying to generate 14 resize versions per upload,” ) – why WordPress trying to generate 14 different sizes? We stucked on this problem for a long time, because we realized that there are a huge amount of same but resized pictures in our server and it decrease our server disk space resources. And the question is: why WordPress always resizes pictures on upload? If Yes, so why is it necessary? And how is it involves a speed, bandwidth, etc?

The settings I mentioned are on the Advanced tab.

WordPress generates 3 resizes per image (by default) as a convenience. As an example, if you generally post 400×600 images on your site, you can set the Medium resize to 400×600. Then, anytime you upload an image, you don’t need to manually resize it beforehand, you simply select the Medium version to insert in your post/page.

But that’s only 3 of 14, right? The rest are generally from your theme. Some responsive themes register more resizes with WordPress than others, but some theme generate a bunch of different sizes for use in headers, widgets, etc. On top of that, some plugins also register a couple resizes, like the woocommerce plugin.
If the resizes are not being used on your site, then you could even turn off the creation of those resizes on the Advanced EWWW settings.