How to open a simple image using streams in Pillow-Python

Question

from PIL import Image


image = Image.open("image.jpg")

file_path = io.BytesIO();

image.save(file_path,'JPEG');


image2 = Image.open(file_path.getvalue());

I get this error TypeError: embedded NUL character on the last statement Image.open on running the program

What is the correct way to open a file from streams?

Answer 1

http://effbot.org/imagingbook/introduction.htm#more-on-reading-images

from PIL import Image
import StringIO

buffer = StringIO.StringIO()
buffer.write(open('image.jpeg', 'rb').read())
buffer.seek(0)

image = Image.open(buffer)
print image
# <PIL.JpegImagePlugin.JpegImageFile image mode=RGB size=800x600 at 0x7FE2EEE2B098>

# if we try open again
image = Image.open(buffer)

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/dist-packages/PIL/Image.py", line 2028, in open
   raise IOError("cannot identify image file")
IOError: cannot identify image file

Make sure you call buff.seek(0) before reading any StringIO objects. Otherwise you'll be reading from the end of the buffer, which will look like an empty file and is likely causing the error you're seeing.

Answer 2

Using BytesIO is much more simple, it took me a while to figure out. This allows you to read and write to zip files for example.

from PIL import Image
from io import BytesIO

# bytes of a simple 2x2 gif file
gif_bytes = b'\x47\x49\x46\x38\x39\x61\x02\x00\x02\x00\x80\x00\x00\x00\xFF\xFF\xFF\x21\xF9\x04\x00\x00\x00\x00\x00\x2C\x00\x00\x00\x00\x02\x00\x02\x00\x00\x02\x03\x44\x02\x05\x00\x3B'
gif_bytes_io = BytesIO() # or io.BytesIO()

# store the gif bytes to the IO and open as image
gif_bytes_io.write(gif_bytes)
image = Image.open(gif_bytes_io)

# optional proof of concept:
# image.show()

# save as png through a stream
png_bytes_io = BytesIO() # or io.BytesIO()
image.save(png_bytes_io, format='PNG')
print(png_bytes_io.getvalue()) # outputs the byte stream of the png