How to get the format of image with PIL?

NeoWang picture NeoWang · Sep 20, 2015 · Viewed 38.4k times · Source

After loading an image file with PIL.Image, how can I determine whether the image file is a PNG/JPG/BMP/GIF? I understand very little about these file formats, can PIL get the format metadata from the file header? Or does it need to 'analyze' the data within the file?

If PIL doesn't provide such an API, is there any python library that does?