Thank you for your response. Tell me then please, how much time did you devote before you wrote your thread?
Checking your site in Dev Tools, I can see that the images are visible in WebP format:
View post on imgur.com
There are several images in the original formats, as indicated by the result in Google PageSpeed Insights:
View post on imgur.com
And why do you get this error? Because these images come from a completely different domain (fbcdn.net), not yours. The plugin supports images located on your server.
Do you know why I write in such an automatic way? Because you can check it yourself by reading the FAQ. The answer is one of the first questions. However, it is always better to write new thread in the technical support section. Believe me, there were already many such cases. And should I write the same to everyone?
Very often I could help users very quickly if they had read the FAQ and in their message they gave me all the information I was asking for. And they are described in detail in the FIRST question in the FAQ. Do not you think that if someone does not give this information in his messages it means that not even taken the time to read the FAQ?
By opening the support thread you have clear information (on a yellow background): “Search the forums to see if your topic has been resolved already.”.
And additionally, a FAQ was created for some purpose. In order to answer common questions there. Just because I wrote the plugin does not mean that I am able to spend a few hours a day writing back to people on the same problems. Please do not compare paid versions here, because this is not a paid plugin. Very often in paid plugins buying it you pay for premium support, among others. Then the assistant will do everything for you.
When a new problem occurs, I try to help. Look at other threads and you will see that I am very active and I care about users of my plugins.