Retrieve a list of supported read file extensions/formats

Question

Here is a list of all image formats that Pillow supports. Since I want to check formats in my application without opening the image and the list of formats will probably change in the future, I wonder if there is an option to retrieve a list of supported file extensions/formats programmatically?

I want to do something like this:

>>> <import something from Pillow>
>>> formats = <call something from Pillow>
>>> formats
["jpg", "jpeg", "png", ...]

I am especially interested in reading formats (so writing does not need to be supported).

Answer 1

You can use features:

from PIL import features
from io import StringIO

# Create buffer for pilinfo() to write into rather than stdout
buffer = StringIO()
features.pilinfo(out=buffer)

# Parse and analyse lines
for line in buffer.getvalue().splitlines():
    print(line)

Sample Output

--------------------------------------------------------------------
Pillow 9.0.1
Python 3.10.0 (v3.10.0:b494f5935c, Oct  4 2021, 14:59:19) [Clang 12.0.5 (clang-1205.0.22.11)]
--------------------------------------------------------------------
Python modules loaded from /Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/PIL
Binary modules loaded from /Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/PIL
--------------------------------------------------------------------
--- PIL CORE support ok, compiled for 9.0.1
--- TKINTER support ok, loaded 8.6
--- FREETYPE2 support ok, loaded 2.11.1
--- LITTLECMS2 support ok, loaded 2.13
--- WEBP support ok, loaded 1.2.2
--- WEBP Transparency support ok
--- WEBPMUX support ok
--- WEBP Animation support ok
--- JPEG support ok, compiled for libjpeg-turbo 2.1.2
--- OPENJPEG (JPEG2000) support ok, loaded 2.4.0
--- ZLIB (PNG/ZIP) support ok, loaded 1.2.11
--- LIBTIFF support ok, loaded 4.2.0
*** RAQM (Bidirectional Text) support not installed
*** LIBIMAGEQUANT (Quantization method) support not installed
--- XCB (X protocol) support ok
--------------------------------------------------------------------
BLP
Extensions: .blp
Features: open
--------------------------------------------------------------------
BMP image/bmp
Extensions: .bmp
Features: open, save
--------------------------------------------------------------------
BUFR
Extensions: .bufr
Features: open, save
--------------------------------------------------------------------
CUR
Extensions: .cur
Features: open
--------------------------------------------------------------------
DCX
Extensions: .dcx
Features: open
--------------------------------------------------------------------
DDS
Extensions: .dds
Features: open, save
--------------------------------------------------------------------
DIB image/bmp
Extensions: .dib
Features: open, save
--------------------------------------------------------------------
EPS application/postscript
Extensions: .eps, .ps
Features: open, save
--------------------------------------------------------------------
FITS
Extensions: .fit, .fits
Features: open, save
--------------------------------------------------------------------
FLI
Extensions: .flc, .fli
Features: open
--------------------------------------------------------------------
FTEX
Extensions: .ftc, .ftu
Features: open
--------------------------------------------------------------------
GBR
Extensions: .gbr
Features: open
--------------------------------------------------------------------
GIF image/gif
Extensions: .gif
Features: open, save, save_all
--------------------------------------------------------------------
GRIB
Extensions: .grib
Features: open, save
--------------------------------------------------------------------
HDF5
Extensions: .h5, .hdf
Features: open, save
--------------------------------------------------------------------
ICNS image/icns
Extensions: .icns
Features: open, save
--------------------------------------------------------------------
ICO image/x-icon
Extensions: .ico
Features: open, save
--------------------------------------------------------------------
IM
Extensions: .im
Features: open, save
--------------------------------------------------------------------
IMT
Features: open
--------------------------------------------------------------------
IPTC
Extensions: .iim
Features: open
--------------------------------------------------------------------
JPEG image/jpeg
Extensions: .jfif, .jpe, .jpeg, .jpg
Features: open, save
--------------------------------------------------------------------
JPEG2000 image/jp2
Extensions: .j2c, .j2k, .jp2, .jpc, .jpf, .jpx
Features: open, save
--------------------------------------------------------------------
MCIDAS
Features: open
--------------------------------------------------------------------
MPEG video/mpeg
Extensions: .mpeg, .mpg
Features: open
--------------------------------------------------------------------
MSP
Extensions: .msp
Features: open, save, decode
--------------------------------------------------------------------
PCD
Extensions: .pcd
Features: open
--------------------------------------------------------------------
PCX image/x-pcx
Extensions: .pcx
Features: open, save
--------------------------------------------------------------------
PIXAR
Extensions: .pxr
Features: open
--------------------------------------------------------------------
PNG image/png
Extensions: .apng, .png
Features: open, save, save_all
--------------------------------------------------------------------
PPM image/x-portable-anymap
Extensions: .pbm, .pgm, .pnm, .ppm
Features: open, save
--------------------------------------------------------------------
PSD image/vnd.adobe.photoshop
Extensions: .psd
Features: open
--------------------------------------------------------------------
SGI image/sgi
Extensions: .bw, .rgb, .rgba, .sgi
Features: open, save
--------------------------------------------------------------------
SPIDER
Features: open, save
--------------------------------------------------------------------
SUN
Extensions: .ras
Features: open
--------------------------------------------------------------------
TGA image/x-tga
Extensions: .icb, .tga, .vda, .vst
Features: open, save
--------------------------------------------------------------------
TIFF image/tiff
Extensions: .tif, .tiff
Features: open, save, save_all
--------------------------------------------------------------------
WEBP image/webp
Extensions: .webp
Features: open, save, save_all
--------------------------------------------------------------------
WMF
Extensions: .emf, .wmf
Features: open, save
--------------------------------------------------------------------
XBM image/xbm
Extensions: .xbm
Features: open, save
--------------------------------------------------------------------
XPM image/xpm
Extensions: .xpm
Features: open
--------------------------------------------------------------------
XVTHUMB
Features: open
--------------------------------------------------------------------

---

There is also:

print(features.get_supported_codecs())
['jpg', 'jpg_2000', 'zlib', 'libtiff']

---

You can also check from outside of your Python interpreter like this:

python3 -m PIL

Answer 2

With the help of @Mark Setchell from the previous answer and with a bit of browsing through the Pillow features module, I produced a complete code that gives me a set of all image file extensions that can be opened by Pillow.

from PIL import Image

exts = Image.registered_extensions()
supported_extensions = {ex for ex, f in exts.items() if f in Image.OPEN}

Answer 3

Thanks @primoz for the answer. I managed to get it working in Python/Flask using the following:

from PIL import Image

exts = Image.registered_extensions()
supported_extensions = [ex[1: for ex, f in exts.items() if f in Image.OPEN]

And then in the form:

picture = FileField('Update Profile Picture', validators=[FileAllowed(supported_extensions)])