Default is Irfanview. I can view the attached files by opening with Irfanview. But they don't appear embedded in the email.
Ah! I thought you can't open & view the attachments, but you can.
It's having them embedded in the body of the email that you are querying.
Perhaps Irfanview isn't compatible with being embedded in emails. Try changing your Default .JPG viewer to Windows Picture & Fax Viewer or Windows Photo Viewer.
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC