Question

How can I programatically set the lock screen image in Windows Phone 7? If this is not possible how can I add an image to the camera roll programatically?

Answer 1

Don’t think you can do this directly, but you can save the image to the user’s picture
library where the user could then choose to use the image for their lock screen image:

Photos, Photos, Photos – How To Save, Load And Iterate Pictures With Windows Phone 7

// Saves the WriteableBitmap encoded as JPEG to the Media library.
// The quality for JPEG encoding has to be in the range 0-100,
// where 100 is the best quality with the largest size.
void SaveToMediaLibrary(this WriteableBitmap bitmap, string name, int quality);

// Saves the WriteableBitmap encoded as JPEG to the Media library
// using the best quality of 100.
void SaveToMediaLibrary(this WriteableBitmap bitmap, string name);