- Go to https://www.swisstopo.admin.ch/en/geodata/images/ortho/swissimage10.html#download
- Choose a selection mode (rectangle, polygon, municipality, ...)
- Set your options, click on search, click on export all link and download the CSV file
- Prefix each URL in the CSV file with the string "/vsicurl/"
- Run
gdalbuildvrt -input_file_list yourDownloadedFile.csv yourOutputFile.vrt
- Use yourOutputFile.vrt in QGIS or with gdal