How to change the lock pictures on the samsung solstice?

I got a new samsung solstice and every time it locks or unlocks there are about 8 different pictures that show up. Is there a way to change or delete the pictures that show up. i would like to have the pictures that i have taken to show up instead of the phones default ones. Also can i download apps and put on the phone via pc and usb cable instead of 3g.
How to change the lock pictures on the samsung solstice?
it's call screensaver, you can create new screenshot using a custom tool on www.samsung-solstice.com

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