ArcGIS 10 image to black edge

In the Guardian Film Law enforcement project, the need for multiple image overlay, which will appear black edge overlay situation, it is necessary to deal with multiple images. There are two main ways of handling this:
Taking ArcGIS10.1 as an example, the operation is as follows:
1. acrtoolbox--> Data management Tools--grid----------------Copy the Rasters--and change the NoData value to 0.
2. Click Raster Data--Properties----Display background value (0,0,0)--and the background value is set to transparent display.

ArcGIS 10 image to black edge