matplotlib:

import matplotlib.image

matplotlib.image.imsave('name.png', array)

适用于matplotlib 1.3.1，我不知道低版本。从文档字符串:

Arguments:
  *fname*:
    A string containing a path to a filename, or a Python file-like object.
    If *format* is *None* and *fname* is a string, the output
    format is deduced from the extension of the filename.
  *arr*:
    An MxN (luminance), MxNx3 (RGB) or MxNx4 (RGBA) array.

您可以使用PyPNG。它是一个纯Python(无依赖)开源PNG编码器/解码器，它支持将NumPy数组写入图像。

如果你有matplotlib，你可以这样做:

import matplotlib.pyplot as plt
plt.imshow(matrix) #Needs to be in row,col order
plt.savefig(filename)

这将保存情节(而不是图像本身)。

@ideasman42回答的附录:

def saveAsPNG(array, filename):
    import struct
    if any([len(row) != len(array[0]) for row in array]):
        raise ValueError, "Array should have elements of equal size"

                                #First row becomes top row of image.
    flat = []; map(flat.extend, reversed(array))
                                 #Big-endian, unsigned 32-byte integer.
    buf = b''.join([struct.pack('>I', ((0xffFFff & i32)<<8)|(i32>>24) )
                    for i32 in flat])   #Rotate from ARGB to RGBA.

    data = write_png(buf, len(array[0]), len(array))
    f = open(filename, 'wb')
    f.write(data)
    f.close()

所以你可以这样做:

saveAsPNG([[0xffFF0000, 0xffFFFF00],
           [0xff00aa77, 0xff333333]], 'test_grid.png')

生产test_grid.png:

(透明性也可以通过减少0xff的高字节来工作。)

你可以在Python中使用'skimage'库

例子:

from skimage.io import imsave
imsave('Path_to_your_folder/File_name.jpg',your_array)

scipy。Misc给出关于imsave函数的弃用警告，并建议使用imageio代替。

import imageio
imageio.imwrite('image_name.png', img)