I can see what you mean when I test it in IE. I think that you should not add in the image over the background but instead you should just adjust the background directly. You would adjust the store message css like this:
css/home.css
[code]
#storeMessage{
/* background-color: #06245C; remove the background color */
background-image: url(http://localhost/powerstore3/Images/storeMessage_bg.png); /* then set your image to the background URL */


