Simply add this code in your CSS File (search: "a:visited", it's often positioned in the top of the document):

A little introduction: you don't need to know HTML for show/hide User Pics. It's the easiest thing that you can do with my style. The portion of code (image in the bottom) underlined is the DIV element that contain the picture's user. Now we're going to learn how hide the user pictures!
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There are two ways to hide user pictures (specially for MT's users): via HTML or via CSS.
HTML
Simply you must delete the portion of code underlined. So, using this method, you won't view User Picture any more. Do you want leave no trace of User Pictures in the style? Read the next paragraph to discover the other way.
CSS
Open magic-book.css and search this code: " .entry-userpic, comment-userpic ". After this, delete all the code in parenthesis (and the code in bold, of course!). Now any reference to User Pics is deleted for ever and ever!
Don't never forget to set "width: 99%" (image above this paragraph) entry-footer, comment-footer, trackbacks-footer.
Write the underlined text every time you encounter the paragraph's class "entry-footer, comment-footer, trackbacks-footer" (image above this paragraph). Remember to paste the code after paragraph's closure for a correct visualization!
Add " /* " before the propriety "display: none;" for disable it. Hereafter the User Picture is visible.
And now an IMPORTANT step! Set width of entry-footer, comment-footer, trackbacks-footer, following these rules:
How do I set width and height of my User Picture?
Simply, search ".entry-userpic img,.comment-userpic img " in the CSS file and set width and height.