When loading big images, I had the «HTTP error» appearing. After googling, I saw that it was a recurrent problem, and many forums discuss it. Some said the problem came from other plugins; they uninstalled them and it worked. I tried with most of my plugins (not all of them, I admit), but I don't think it is the problem because I succeeded to load a small image.
Then I also found on some forums that it could be linked to file permissions, and I did verify that.
Finally, I found that it could be linked to the RAM. Some people suggested to modify and server configuration (and apache/php), but it is not my website so I would like to avoid that. Some people suggested to modify .htaccess. I did and didn't see any change. Some people suggested to use this plugin (add from server). I did and it seems to work, now at least I see the image in the media library instead of an empty square, but if I look at the page or the article, it doesn't appear.
Can you please tell me what to do next? I am still a beginner with all of this, so please explain precisely.
Thank you very much!