You can apply a custom image to an asset you own using CPs.
Click your CP total, select Exchange CPs, scroll down to Custom Images. And I think the rest of the instructions are pretty straight forward.
Of course you have to host the images somewhere on the internet, whether it's personal hosting, photobucket, imageshack, or whatever.
____________"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Only fools and children dream of heroes.