margin: 0px auto !important;
   max-width: 680px;
   width: 100%;

I have used the userChrome.css file to change the width of the messages container. The only css that I have used is this: hbox#messagepaneboxwrapper #messagepanebox #messagepane { margin: 0px auto !important; max-width: 680px; width: 100%; } The issue is that when I open an email I received, sometimes the inline images are having a width 100% of the parent container (when I first open the message after the TB restart for first time), as they should be and sometimes the inline images are having their actual size. In the first case the img element has the parameters overflow and shrinktofit as TRUE img src="imap://................@imap.gmail.com:993/fetch%3EUID%3E/INBOX%3E33514?part=1.1.2&filename=Screenshot%202024-10-13%20at%2017.50.33.jpeg" alt="Screenshot 2024-10-13 at 17.50.33.jpeg" overflowing="true" shrinktofit="true" In the second case the img element has only the parameter shrinktofit as TRUE img src="imap://................@imap.gmail.com:993/fetch%3EUID%3E/INBOX%3E33514?part=1.1.2&filename=Screenshot%202024-10-13%20at%2017.50.33.jpeg" alt="Screenshot 2024-10-13 at 17.50.33.jpeg" shrinktofit="true" I'm attaching 3 photos where you can see how the photos are handled differently when I open the message, close it and then reopen it. In addition, in the case of fulled sized photos, the cursor does not change to a zoom lens when passing over them and I can not zoom-in or zoom out them.