IOError: cannot identify image file -- works locally but not on Heroku

Question

I know there are a zillion questions and answers about this error on StackOverflow, and I have read them all and tried many of their suggestions (Pillow instead of PIL, io.BytesIO instead of stringIO), but I'm still getting the same issue with the following:

I'm working on code to process images from S3 -- specifically to resave them as JPGs, rotate them if necessary, and create various thumbnails. The relevant part of the code gets a list of URLs referring to images on S3. I can confirm that, yes, the images are on S3 in the location specified by the URL. On each URL I call the following:

def process_new_image(file_url):        
    # Load the image and make it a PIL object
    try:
        fd = urllib.urlopen(file_url)
        image_file = io.BytesIO(fd.read())
        image = Image.open(image_file)
    except Exception, e:
        # ===> This is where the issue happens. <====
        raise

    # Read the exif data and potentially rotate the image
    transpose = Transpose()
    transposed_image = transpose.process(image)

    # Resave the image as a jpeg
    new_image_data = io.BytesIO()
    transposed_image.save(new_image_data, 'jpeg', quality=100)
    new_image_data.seek(0)

    try:
        self.image.save('image', ContentFile(new_image_data.read()), save=True)
    except Exception, e:         
        raise

    new_image_data.seek(0)
    self.process_thumbnails(new_image_data)

This code works fine locally. But when I run it on my staging environment in Heroku, I get "IOError: cannot identify image file." It fails on JPGs, PNGs, and GIFs, which all work locally.

Specifics about my environment:

Django==1.5.1

Pillow==2.1.0

pilkit==1.1.1

Python 2.7.3 (on both)

Locally Pillow compiled with:

--- TKINTER support available
--- JPEG support available
--- ZLIB (PNG/ZIP) support available
*** TIFF G3/G4 (experimental) support not available
--- FREETYPE2 support available
*** LITTLECMS support not available
*** WEBP support not available

On Heroku Pillow compiled with:

       *** TKINTER support not available
       --- JPEG support available
       --- ZLIB (PNG/ZIP) support available
       --- TIFF G3/G4 (experimental) support available
       --- FREETYPE2 support available
       --- LITTLECMS support available
       *** WEBP support not available

Answer 1

Issue related to S3 bucket. Image needed to be made public in bucket. Question should be closed.