What is the best way to do this? I have two images that overlap about 20%, and they are 4 bands each. Same satellite provider, resolution, etc. so there's no apparent issue with alignment. Each file is a little under 1.5 Gb.
My method was was to build a VRT where I selected each of the two overlapping layers, unchecked
place each input file into a separate band (I don't understand what this does).
Then I used GDAL translate to convert the VRT back into a GeoTIFF. After I did this, the file grew to 6.5 Gb. How is that possible if each separate file was < 1.5 Gb? All other parameters were left to default in QGIS.