Image file formats

The Python Imaging Library supports a wide variety of raster file formats. Nearly 30 different file formats can be identified and read by the library. Write support is less extensive, but most common interchange and presentation formats are supported.

The open() function identifies files from their contents, not their names, but the save() method looks at the name to determine which format to use, unless the format is given explicitly.

Fully supported formats

BMP

PIL reads and writes Windows and OS/2 BMP files containing 1, L, P, or RGB data. 16-colour images are read as P images. Run-length encoding is not supported.

The open() method sets the following info properties:

compression
Set to bmp_rle if the file is run-length encoded.

EPS

PIL identifies EPS files containing image data, and can read files that contain embedded raster images (ImageData descriptors). If Ghostscript is available, other EPS files can be read as well. The EPS driver can also write EPS images.

GIF

PIL reads GIF87a and GIF89a versions of the GIF file format. The library writes run-length encoded GIF87a files. Note that GIF files are always read as grayscale (L) or palette mode (P) images.

The open() method sets the following info properties:

background
Default background color (a palette color index).
duration
Time between frames in an animation (in milliseconds).
transparency
Transparency color index. This key is omitted if the image is not transparent.
version
Version (either GIF87a or GIF89a).

Reading sequences

The GIF loader supports the seek() and tell() methods. You can seek to the next frame (im.seek(im.tell() + 1), or rewind the file by seeking to the first frame. Random access is not supported.

Reading local images

The GIF loader creates an image memory the same size as the GIF file’s logical screen size, and pastes the actual pixel data (the local image) into this image. If you only want the actual pixel rectangle, you can manipulate the size and tile attributes before loading the file:

im = Image.open(...)

if im.tile[0][0] == "gif":
    # only read the first "local image" from this GIF file
    tag, (x0, y0, x1, y1), offset, extra = im.tile[0]
    im.size = (x1 - x0, y1 - y0)
    im.tile = [(tag, (0, 0) + im.size, offset, extra)]

IM

IM is a format used by LabEye and other applications based on the IFUNC image processing library. The library reads and writes most uncompressed interchange versions of this format.

IM is the only format that can store all internal PIL formats.

JPEG

PIL reads JPEG, JFIF, and Adobe JPEG files containing L, RGB, or CMYK data. It writes standard and progressive JFIF files.

Using the draft() method, you can speed things up by converting RGB images to L, and resize images to 1/2, 1/4 or 1/8 of their original size while loading them. The draft() method also configures the JPEG decoder to trade some quality for speed.

The open() method sets the following info properties:

jfif
JFIF application marker found. If the file is not a JFIF file, this key is not present.
adobe
Adobe application marker found. If the file is not an Adobe JPEG file, this key is not present.
progression
Indicates that this is a progressive JPEG file.

The save() method supports the following options:

quality
The image quality, on a scale from 1 (worst) to 95 (best). The default is 75. Values above 95 should be avoided; 100 disables portions of the JPEG compression algorithm, and results in large files with hardly any gain in = image quality.
optimize
If present, indicates that the encoder should make an extra pass over the image in order to select optimal encoder settings.
progressive
If present, indicates that this image should be stored as a progressive JPEG file.

Note

To enable JPEG support, you need to build and install the IJG JPEG library before building the Python Imaging Library. See the distribution README for details.

MSP

PIL identifies and reads MSP files from Windows 1 and 2. The library writes uncompressed (Windows 1) versions of this format.

PCX

PIL reads and writes PCX files containing 1, L, P, or RGB data.

PNG

PIL identifies, reads, and writes PNG files containing 1, L, P, RGB, or RGBA data. Interlaced files are supported as of v1.1.7.

The open() method sets the following info properties, when appropriate:

gamma
Gamma, given as a floating point number.
transparency
Transparency color index. This key is omitted if the image is not a transparent palette image.

The save() method supports the following options:

optimize
If present, instructs the PNG writer to make the output file as small as possible. This includes extra processing in order to find optimal encoder settings.
transparency
For P and L images, this option controls what color image to mark as transparent.
bits (experimental)
For P images, this option controls how many bits to store. If omitted, the PNG writer uses 8 bits (256 colors).
dictionary (experimental)
Set the ZLIB encoder dictionary.

Note

To enable PNG support, you need to build and install the ZLIB compression library before building the Python Imaging Library. See the distribution README for details.

PPM

PIL reads and writes PBM, PGM and PPM files containing 1, L or RGB data.

SPIDER

PIL reads and writes SPIDER image files of 32-bit floating point data (“F;32F”).

PIL also reads SPIDER stack files containing sequences of SPIDER images. The seek() and tell() methods are supported, and random access is allowed.

The open() method sets the following attributes:

format
Set to SPIDER
istack
Set to 1 if the file is an image stack, else 0.
nimages
Set to the number of images in the stack.

A convenience method, convert2byte(), is provided for converting floating point data to byte data (mode L):

im = Image.open('image001.spi').convert2byte()

Writing files in SPIDER format

The extension of SPIDER files may be any 3 alphanumeric characters. Therefore the output format must be specified explicitly:

im.save('newimage.spi', format='SPIDER')

For more information about the SPIDER image processing package, see the SPIDER home page at Wadsworth Center.

TIFF

PIL reads and writes TIFF files. It can read both striped and tiled images, pixel and plane interleaved multi-band images, and either uncompressed, or Packbits, LZW, or JPEG compressed images.

If you have libtiff and its headers installed, PIL can read and write many more kinds of compressed TIFF files. If not, PIL will always write uncompressed files.

The open() method sets the following info properties:

compression
Compression mode.
dpi

Image resolution as an (xdpi, ydpi) tuple, where applicable. You can use the tag attribute to get more detailed information about the image resolution.

New in version 1.1.5.

In addition, the tag attribute contains a dictionary of decoded TIFF fields. Values are stored as either strings or tuples. Note that only short, long and ASCII tags are correctly unpacked by this release.

WebP

PIL reads and writes WebP files. The specifics of PIL’s capabilities with this format are currently undocumented.

XBM

PIL reads and writes X bitmap files (mode 1).

XV Thumbnails

PIL can read XV thumbnail files.

Read-only formats

CUR

CUR is used to store cursors on Windows. The CUR decoder reads the largest available cursor. Animated cursors are not supported.

DCX

DCX is a container file format for PCX files, defined by Intel. The DCX format is commonly used in fax applications. The DCX decoder can read files containing 1, L, P, or RGB data.

When the file is opened, only the first image is read. You can use seek() or ImageSequence to read other images.

FLI, FLC

PIL reads Autodesk FLI and FLC animations.

The open() method sets the following info properties:

duration
The delay (in milliseconds) between each frame.

FPX

PIL reads Kodak FlashPix files. In the current version, only the highest resolution image is read from the file, and the viewing transform is not taken into account.

Note

To enable full FlashPix support, you need to build and install the IJG JPEG library before building the Python Imaging Library. See the distribution README for details.

GBR

The GBR decoder reads GIMP brush files.

The open() method sets the following info properties:

description
The brush name.

GD

PIL reads uncompressed GD files. Note that this file format cannot be automatically identified, so you must use PIL.GdImageFile.open() to read such a file.

The open() method sets the following info properties:

transparency
Transparency color index. This key is omitted if the image is not transparent.

ICO

ICO is used to store icons on Windows. The largest available icon is read.

IMT

PIL reads Image Tools images containing L data.

IPTC/NAA

PIL provides limited read support for IPTC/NAA newsphoto files.

MCIDAS

PIL identifies and reads 8-bit McIdas area files.

MIC (read only)

PIL identifies and reads Microsoft Image Composer (MIC) files. When opened, the first sprite in the file is loaded. You can use seek() and tell() to read other sprites from the file.

PCD

PIL reads PhotoCD files containing RGB data. By default, the 768x512 resolution is read. You can use the draft() method to read the lower resolution versions instead, thus effectively resizing the image to 384x256 or 192x128. Higher resolutions cannot be read by the Python Imaging Library.

PSD

PIL identifies and reads PSD files written by Adobe Photoshop 2.5 and 3.0.

SGI

PIL reads uncompressed L, RGB, and RGBA files.

TGA

PIL reads 24- and 32-bit uncompressed and run-length encoded TGA files.

WAL

New in version 1.1.4.

PIL reads Quake2 WAL texture files.

Note that this file format cannot be automatically identified, so you must use the open function in the WalImageFile module to read files in this format.

By default, a Quake2 standard palette is attached to the texture. To override the palette, use the putpalette method.

XPM

PIL reads X pixmap files (mode P) with 256 colors or less.

The open() method sets the following info properties:

transparency
Transparency color index. This key is omitted if the image is not transparent.

Write-only formats

PALM

PIL provides write-only support for PALM pixmap files.

The format code is Palm, the extension is .palm.

PDF

PIL can write PDF (Acrobat) images. Such images are written as binary PDF 1.1 files, using either JPEG or HEX encoding depending on the image mode (and whether JPEG support is available or not).

PIXAR (read only)

PIL provides limited support for PIXAR raster files. The library can identify and read “dumped” RGB files.

The format code is PIXAR.

Identify-only formats

BUFR

New in version 1.1.3.

PIL provides a stub driver for BUFR files.

To add read or write support to your application, use PIL.BufrStubImagePlugin.register_handler().

FITS

New in version 1.1.5.

PIL provides a stub driver for FITS files.

To add read or write support to your application, use PIL.FitsStubImagePlugin.register_handler().

GRIB

New in version 1.1.5.

PIL provides a stub driver for GRIB files.

The driver requires the file to start with a GRIB header. If you have files with embedded GRIB data, or files with multiple GRIB fields, your application has to seek to the header before passing the file handle to PIL.

To add read or write support to your application, use PIL.GribStubImagePlugin.register_handler().

HDF5

New in version 1.1.5.

PIL provides a stub driver for HDF5 files.

To add read or write support to your application, use PIL.Hdf5StubImagePlugin.register_handler().

MPEG

PIL identifies MPEG files.

WMF

PIL can identify placable WMF files.

In PIL 1.1.4 and earlier, the WMF driver provides some limited rendering support, but not enough to be useful for any real application.

In PIL 1.1.5 and later, the WMF driver is a stub driver. To add WMF read or write support to your application, use PIL.WmfImagePlugin.register_handler() to register a WMF handler.

from PIL import Image
from PIL import WmfImagePlugin

class WmfHandler:
    def open(self, im):
        ...
    def load(self, im):
        ...
        return image
    def save(self, im, fp, filename):
        ...

wmf_handler = WmfHandler()

WmfImagePlugin.register_handler(wmf_handler)

im = Image.open("sample.wmf")