title: Saving a large color image as `GTiff` with `gdal`
body: <p>I'm trying to save a large image of size <code>(15000, 80000, 3)</code>. This array is a numpy array that I initialized as <code>im_final = np.zeros((15000,80000,,3))</code>. To do the saving, I use <code>gdal</code> like so:</p>
  
  <pre><code>dst_ds = gdal.GetDriverByName('GTiff').Create('val.tif', 80000, 15000, 3, gdal.GDT_Byte)
  dst_ds.GetRasterBand(1).WriteArray(im_final[:,:,0])   # write r-band to the    raster
  dst_ds.GetRasterBand(2).WriteArray(im_final[:,:,1])   # write g-band to the raster
  dst_ds.GetRasterBand(3).WriteArray(im_final[:,:,2])   # write b-band to the raster
  dst_ds.FlushCache()                     # write to disk
  dst_ds = None
  </code></pre>
  
  <p>When I save it, the resulting image is black and white. However, I need the image to be RGB, does anyone know what the issue is? Furthermore, the values in <code>im_final</code> are <code>uint16</code>.</p>