[gdal-dev] Cannot set transparent color for GeoTIFFs processed by gdal_retile

[Ralf Wagner]

Hello,
I am creating image pyramid from a bunch of color GeoTIFF files using
"gdal_retile" tool. I have managed to generate pyramid but unfortunately
there is a problem - my GeoTIFFs maps overlap and have white margins
around and I am unable to force GDAL to treat white color as transparent
to avoid covering maps by these margins. I have tried all ideas I could
imagine but to no avail. So my question is: how to tweak "gdal_retile"
to get white color treated as transparent during merging?
I am using GDAL 1.6 on Windows. Any help will be very, very appreciated
- thank you.

-- 
Ralf Wagner