[bug fix] change image file detector

requirements.txt

@@ -9,3 +9,4 @@ tqdm==4.51.0
 requests==2.24.0
 scipy==1.5.4
 pymatting==1.1.1
+filetype=1.0.7

src/rembg/cmd/cli.py

@@ -2,6 +2,7 @@ import argparse
 import glob
 import imghdr
 import os
+import filetype
 from distutils.util import strtobool
 
 from ..bg import remove
@@ -90,7 +91,10 @@ def main():
                 full_paths += glob.glob(path + "/*")
 
         for fi in files:
-            if imghdr.what(fi) is None:
+            fi_type = filetype.guess(fi)
+            if fi_type is None:
+                continue
+            elif if_type.mime.find('image') < 0:
                 continue
 
             with open(fi, "rb") as input: