python生成指定尺寸的縮略圖

python生成指定尺寸的縮略圖，先對圖片進行縮小，然后進行裁剪，直到生成規定的尺寸

def MakeThumb(path, sizes=(75, 32, 16)):
    """
    縮略圖生成程序 by Neil Chen
    sizes 參數傳遞要生成的尺寸，可以生成多種尺寸
    """
    base, ext = os.path.splitext(path)
    try:
        im = Image.open(path)
    except IOError:
        return
    mode = im.mode
    if mode not in ('L', 'RGB'):
        if mode == 'RGBA':


        # 透明圖片需要加白色底
        alpha = im.split()[3]
        bgmask = alpha.point(lambda x: 255-x)
        im = im.convert('RGB')
        # paste(color, box, mask)
        im.paste((255,255,255), None, bgmask)
    else:
        im = im.convert('RGB')

width, height = im.size
if width == height:
    region = im
else:
    if width > height:
        delta = (width - height)/2
        box = (delta, 0, delta+height, height)
    else:
        delta = (height - width)/2
        box = (0, delta, width, delta+width)
    region = im.crop(box)

for size in sizes:
    filename = base + "_" + "%sx%s" % (str(size), str(size)) + ".jpg"
    thumb = region.resize((size,size), Image.ANTIALIAS)
    thumb.save(filename, quality=100) # 默認 JPEG 保存質量是 75, 不太清楚。可選值(0~100)</pre>