Transparent raster layer

[Pleyer, Walter]

Good morning, Frank!

> Are you wanting to return an image from mapserver where the 
> final image includes alpha type transparency?  What is your 
> output format?
Our goal is to generate an image, that is composed of two input images, 
for example one satelite image (tiff) and a DEM (also tiff), where the 
DEM is on top and 50% transparent, so that the resulting image as a 
pseudo 3D look.
The resulting image does not need to be transparent.
For the output format png is preferred, but jpg is also an option.

thanks in advance
Walter