Matanuska Glacier Cave, Alaska
Photograph by George F. Mobley
Just downloaded this wallpaper from National Geography website, nice picture of Matanuska Clacier Cave.
Meltwater sculpted the dagger-like shaft of ice near a cave in Matanuska Glacier in Alaska's Chugach Mountains. Matanuska is an active glacier, advancing about one foot (0.3 meters) every day.
Matanuska Glacier Cave, Alaska




To create a gradual blurring (none at the bottom to maximum at the top), create a new alpha channel and apply a gradient so that the channel is white at the top of the image and black at the bottom. 

