How to use lsd_slam using png files not bag file? [closed]

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I use fuerte and ubuntu 12.04. I install lsd_slam code and try to run it. Firstly, I run below command :

fuerte_workspace$ roscore
fuerte_workspace$ rosrun lsd_slam_viewer viewer
fuerte_workspace$ rosrun lsd_slam_core live_slam image:=/image_raw camera_info:=/camera_info
fuerte_workspace$ rosbag play LSD_room.bag

LSD_room.bag file was downloaded from here.

If I want to use png files, how can I run this example? Should I convert png or video to bag file?