Python Wand 将 img 文件作为 blob 打开,md5 不正确。
with Image(filename=picture) as img:
blob = img.make_blob()
print 'blob md5', hashlib.md5(blob).hexdigest()
with open(picture, 'rb') as img:
content = img.read()
print 'content md5', hashlib.md5(content).hexdigest()