Create a geotiff from an existing bitmap in C# with gdal

I have to use gdal in a c# project. The thing I have to do is to "convert" a simple bitmap into a GeoTiff. I read some documentation on the gdal website but I didn't succeed to make it work perfectly. In fact my bitmap is successfuly exported to a geotiff, but if I open the geotiff with a GIS software (for instance QuantumGIS) the GeoTiff is inverted on the y-axis : : Whereas the original bitmap look like this : Here is what I've done : First I write a temp file to the disk (that is the bitmap), I create a dataset containing the bitmap thanks to gdal function (Gdal.Open(path)), and I create a new dataset (with the GTiff driver) using the bitmap dataset , I set the geo transformation and I write the geotiff to the disk : ``` String wktProj = null; String tmpPath = @"C:\tmp.bmp"; Bitmap tmpBitmap = bmp.Clone(new Rectangle(0, 0, bmp.Width, bmp.Height), pixFormat); tmpBitmap.Save(tmpPath, ImageFormat.Bmp); String[] options = null; Gdal.AllRegister(); OSGeo.GDAL.Driver srcDrv = Gdal.GetDriverByName("GTiff"); Dataset srcDs = Gdal.Open(tmpPath, Access.GA_ReadOnly); Dataset dstDs = srcDrv.CreateCopy(path, srcDs, 0, options, null, null); //Set the map projection Osr.GetWellKnownGeogCSAsWKT("WGS84", out wktProj); dstDs.SetProjection(wktProj); //Set the map georeferencing double mapWidth = Math.Abs(latLongMap.listBounds.topRight.x - latLongMap.listBounds.bottomLeft.x); double mapHeight = Math.Abs(latLongMap.listBounds.topRight.y - latLongMap.listBounds.bottomLeft.y); double[] geoTransfo = new double[] { -5.14, mapWidth / bmp.Width, 0, 48.75, 0, mapHeight / bmp.Height }; dstDs.SetGeoTransform(geoTransfo); dstDs.FlushCache(); dstDs.Dispose(); srcDs.Dispose(); srcDrv.Dispose(); tmpBitmap.Dispose(); File.Delete(tmpPath); ``` Any idea on what I'm doing wrong ? Edit I don't know if it is important but the pixels bitmap are 8bppIndexed.