Ringtones for Phones

I have a Samsung Gloss and on the pictures on google, it shows the background for the chat on messaging is blue. Mine is white on my messaging I would like to know how to change the chat color to blue like in the picture.
here is the link to the picture:

http://www.new-cell-phones.org/wp-content/uploads/2009/05/samsung-gloss-cell-phone-4.jpg