Can JPEGs have overviews?

I was a little surprised to see the output of a .jpg file when gdalinfo said it had overviews.

Can jpegs really have overviews or what does this mean? Can they be removed to reduce file size?

Image Structure Metadata:
  COMPRESSION=JPEG
  INTERLEAVE=PIXEL
  SOURCE_COLOR_SPACE=YCbCr
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0, 4912.0)
Upper Right ( 7360.0,    0.0)
Lower Right ( 7360.0, 4912.0)
Center      ( 3680.0, 2456.0)
Band 1 Block=7360x1 Type=Byte, ColorInterp=Red
  Overviews: 3680x2456, 1840x1228, 920x614
  Image Structure Metadata:
    COMPRESSION=JPEG
Band 2 Block=7360x1 Type=Byte, ColorInterp=Green
  Overviews: 3680x2456, 1840x1228, 920x614
  Image Structure Metadata:
    COMPRESSION=JPEG
Band 3 Block=7360x1 Type=Byte, ColorInterp=Blue
  Overviews: 3680x2456, 1840x1228, 920x614
  Image Structure Metadata:
    COMPRESSION=JPEG