diff --git a/app/scodoc/sco_logos.py b/app/scodoc/sco_logos.py
index 343c4c462f..278cccb9cc 100644
--- a/app/scodoc/sco_logos.py
+++ b/app/scodoc/sco_logos.py
@@ -136,7 +136,9 @@ def _list_dept_logos(dept_id=None, prefix=scu.LOGO_FILE_PREFIX):
             if os.access(path_dir.joinpath(entry).absolute(), os.R_OK):
                 result = filename_parser.match(entry.name)
                 if result:
-                    logoname = result.group(1)[:-1] # retreive logoname from filename (less final dot)
+                    logoname = result.group(1)[
+                        :-1
+                    ]  # retreive logoname from filename (less final dot)
                     logos[logoname] = Logo(logoname=logoname, dept_id=dept_id).select()
     return logos if len(logos.keys()) > 0 else None
 
@@ -235,7 +237,7 @@ class Logo:
             unit = img.info.get("jfif_unit", 0)  # 0 = no unit ; 1 = inch ; 2 = mm
         if self.density is not None:
             x_density, y_density = self.density
-            if unit != 0:
+            if unit != 0 and x_density != 0 and y_density != 0:
                 unit2mm = [0, 1 / 0.254, 0.1][unit]
                 x_mm = round(x_size * unit2mm / x_density, 2)
                 y_mm = round(y_size * unit2mm / y_density, 2)
@@ -244,7 +246,6 @@ class Logo:
                 self.mm = None
         else:
             self.mm = None
-
         self.size = (x_size, y_size)
         self.aspect_ratio = round(float(x_size) / y_size, 2)