diff --git a/prosopopee/prosopopee.py b/prosopopee/prosopopee.py
index 6499e61..dfc474e 100644
--- a/prosopopee/prosopopee.py
+++ b/prosopopee/prosopopee.py
@@ -16,6 +16,7 @@ Options:
 import os
 import shutil
 import socketserver
+import subprocess
 import http.server
 
 import ruamel.yaml as yaml
@@ -266,6 +267,13 @@ class Image(object):
 
         return thumbnail_name
 
+    @property
+    def ratio(self):
+        command = "gm identify -format %w,%h " + self.base_dir.joinpath(self.name)
+        out = subprocess.check_output(command.split())
+        width,height = out.split(',')
+        return float(width) / int(height)
+
     def __repr__(self):
         return self.name