Internet Explorer displays an X when it can’t find an image. Firefox ignores it. Most likely that’s why you see it on one computer and not on the other.
There is an image URL missing in your code – this code (as seen in View Source while looking at your page
<div class="column span-3 append-1">
<a title="Permanent Link to Welcome to Toby n’ Friendz.com!" href="https://www.tobynfriendz.com/2009/09/11/toby-2/"><img class="photo_align_left" alt="" src=""/></a>
If you notice, the src is empty, meaning there is supposed to be an image URL there.
I can see you are using the monochrome_lite theme. There is something funny about the way it is installed. The URL to your stylesheet is
https://www.tobynfriendz.com/blog/wp-content/themes/monochrome_lite/monochrome_lite/style.css
As you see, the monochrome_lite folder is repeated twice. Perhaps you have the theme folder inside an outer folder of the same theme name? Although not definite, this might explain why images are not being found. Most likely it should only be there once. That is, there is an extra level of folders that’s unnecessary.
If that’s not the problem, you have to go through your theme settings to find what its looking for where that image is supposed to be displaying.