It is a mistake to cast to int as other parts or conversion code (i.e. traversal ones)

will read preference as it is. This can lead to a new cache key and thus a new storage in cache.

bt5/erp5_dms_conversion_catalog/SkinTemplateItem/portal_skins/erp5_dms_conversion_catalog/Base_preConvert.xml

@@ -58,7 +58,7 @@ portal = context.getPortalObject()\n
 \n
 portal_type = context.getPortalType()\n
 format = portal.portal_preferences.getPreferredImageFormat()\n
-quality = int(portal.portal_preferences.getPreferredImageQuality())\n
+quality = portal.portal_preferences.getPreferredImageQuality()\n
 preferred_image_size = portal.portal_preferences.getPreferredImageSize()\n
 \n
 # thumbnail is required always\n

bt5/erp5_dms_conversion_catalog/bt/revision

-2
+3
\ No newline at end of file