What I'm saying is your link is wrong in the source code, look at your code again. You'll notice that the image that works has one path...
assets/backgrounds/calendar_background.png
...and the image that doesn't is using a different path...
../Calendars%20By%20Tat/assets/backgrounds/calendar_background.png); (which can't work because it tries to direct the browser above your site's root folder)
Change the second one to match the first and your problem is gone.
In the css of the page...
<!--
.style3 {font-size: 16px}
.style4 {font-style: normal; color: #FFFFFF; font-family: Arial, Helvetica, sans-serif;}
.calendarframe {
border: thin solid #000000;
padding: 10px;
}
.footer {
font-family: Arial, Helvetica, sans-serif;
font-size: 12px;
font-style: normal;
font-weight: normal;
background-image: url(../Calendars%20By%20Tat/assets/backgrounds/calendar_background.png);
}
-->