Extensions: .jfif, .jpe, .jpg, .jpeg

A JPEG format based on Pillow.

This format supports grayscale, RGB and RGBA images.

Parameters for reading

exifrotate : bool
Automatically rotate the image according to exif flag. Default True.
pilmode : str

From the Pillow documentation:

  • ‘L’ (8-bit pixels, grayscale)
  • ‘P’ (8-bit pixels, mapped to any other mode using a color palette)
  • ‘RGB’ (3x8-bit pixels, true color)
  • ‘RGBA’ (4x8-bit pixels, true color with transparency mask)
  • ‘CMYK’ (4x8-bit pixels, color separation)
  • ‘YCbCr’ (3x8-bit pixels, color video format)
  • ‘I’ (32-bit signed integer pixels)
  • ‘F’ (32-bit floating point pixels)

PIL also provides limited support for a few special modes, including ‘LA’ (‘L’ with alpha), ‘RGBX’ (true color with padding) and ‘RGBa’ (true color with premultiplied alpha).

When translating a color image to grayscale (mode ‘L’, ‘I’ or ‘F’), the library uses the ITU-R 601-2 luma transform:

L = R * 299/1000 + G * 587/1000 + B * 114/1000
as_gray : bool
If True, the image is converted using mode ‘F’. When mode is not None and as_gray is True, the image is first converted according to mode, and the result is then “flattened” using mode ‘F’.

Parameters for saving

quality : scalar
The compression factor of the saved image (1..100), higher numbers result in higher quality but larger file size. Default 75.
progressive : bool
Save as a progressive JPEG file (e.g. for images on the web). Default False.
optimize : bool
On saving, compute optimal Huffman coding tables (can reduce a few percent of file size). Default False.
dpi : tuple of int
The pixel density, (x,y).
icc_profile : object
If present and true, the image is stored with the provided ICC profile. If this parameter is not provided, the image will be saved with no profile attached.
exif : dict
If present, the image will be stored with the provided raw EXIF data.
subsampling : str
Sets the subsampling for the encoder. See Pillow docs for details.
qtables : object
Set the qtables for the encoder. See Pillow docs for details.