python-image-complete

Python 3 library for checking whether an image is complete or not. It is either looking for EOF markers or checking the length of the file against one stored in the file.

Can also operate on bytes or BytesIO objects.

By default, the library operates in strict mode, i.e., no trailing junk data is tolerated. However, by supplying the parameters strict and check_size this can turned into lenient mode. The parameter check_size (i.e., the number of bytes to read from the end of the file) is only used for formats gif, jpg, png.

Supported image formats

• BMP (extension: .bmp)
• GIF (extension: .gif)
• JPG (extension: .jpg, .jpeg)
• PNG (extension: .png)
• WebP (extension: .webp)

File structures

• BMP (checks file length)

  • https://en.wikipedia.org/wiki/BMP_file_format#File_structure

• GIF (checks EOF marker)

  • https://en.wikipedia.org/wiki/GIF#File_format

• JPG (checks EOF marker)

  • http://en.wikipedia.org/wiki/JPEG#Syntax_and_structure

• PNG (checks EOF marker)

  • https://en.wikipedia.org/wiki/Portable_Network_Graphics#Critical_chunks
  • http://www.libpng.org/pub/png/spec/1.2/PNG-Structure.html#Chunk-layout
  • http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.IEND

• WebP (compares data length after RIFF header with file length)

  • https://developers.google.com/speed/webp/docs/riff_container

Examples

Auto detection

from image_complete.auto import is_image_complete

# using file names
print(is_image_complete("/some/where/hello_world.jpg"))
print(is_image_complete("/some/where/image.png"))

# using bytes or BytesIO
with open("/some/where/image.bmp", "rb") as fp:
    b = fp.read()
print(is_image_complete(b))

JPG specific

from image_complete.jpg import is_jpg_complete, is_jpg

f = "/some/where/hello_world.jpg"
if is_jpg(f):
    print(is_jpg_complete(f))
else:
    print("Not a JPG!")

Lenient mode (i.e., tolerating trailing junk data)

from image_complete.auto import is_image_complete

# using file names
print(is_image_complete("/some/where/hello_world.jpg", strict=False, check_size=100))
print(is_image_complete("/some/where/image.png", strict=False, check_size=100))

# using bytes or BytesIO
with open("/some/where/image.bmp", "rb") as fp:
    b = fp.read()
print(is_image_complete(b, strict=False))