With GDAL 1.7.2, released 2010/04/23, I used gdalbuildvrt to build a .vrt file that points to 726 GeoTIFF images. Then, I use QGIS 1.5.0, release 13519M to pan and zoom through these images. When zoomed in, how do I get Qgis to identify which ONE of the raster images is currently being displayed? Greg