diff --git a/bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web/WebPage_exportAsSingleFile.py b/bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web/WebPage_exportAsSingleFile.py
index 7c1fe552a0a97d3c930c0fb3615efdee775d8e33..c5858358fee0539569ac6d0a3977c19a8818304a 100644
--- a/bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web/WebPage_exportAsSingleFile.py
+++ b/bt5/erp5_web/SkinTemplateItem/portal_skins/erp5_web/WebPage_exportAsSingleFile.py
@@ -172,7 +172,7 @@ def handleImageSourceObject(obj, src):
         format_kw["display"] = value
     if format_kw:
       mime, data = obj.convert(**format_kw)
-      return handleLinkedData(mime, data, src)
+      return handleLinkedData(mime, str(data), src)
 
   return handleHrefObject(obj, src, default_mimetype=bad_image_mime_type, default_data=bad_image_data)