how do i get the background on my Samsung R451C to fit to screen?

[Michael L]

i just bought a straight talk Samsung R451C phone. i have pics on my sd card that i put in it and selected a pic for my background but it has the white filler around the pic. im sure it has the fit to scrren option but cant find it. im hoping it fits to screen while the keypad is slid out also because the pic is way off when open. thanks!!