diff --git a/safesite/export.py b/safesite/export.py
index 7352543f..69f9800a 100644
--- a/safesite/export.py
+++ b/safesite/export.py
@@ -307,7 +307,7 @@ def exportxlsx(a,objs):
             if v['yhtp']:
                 try:
                     img = Image(dirname + v['yhtp'][0])
-                    if str(img.format)!='MPO':             
+                    if img.format!='mpo':             
                         img.width, img.height = (90, 90)       #这两个属性分别是对应添加图片的宽高    
                         sheet.add_image(img, 'u'+str(i+4))
                 except:
@@ -315,7 +315,7 @@ def exportxlsx(a,objs):
             if v['zghtp']:
                 try:
                     img = Image(dirname + v['zghtp'][0])
-                    if str(img.format)!='MPO':
+                    if img.format!='mpo':
                         img.width, img.height = (90, 90)       #这两个属性分别是对应添加图片的宽高    
                         sheet.add_image(img, 'w'+str(i+4))
                 except: