Outlook 2011 Attachment names get corrupted

I am running Snow Leopard on an iMac with Office 2011. I often want to send pictures to people using Outlook. I find that the attachment name very frequently gets corrupted (so that the last 10 characters or something are random letters / characters).

There used to be a switch in Entourage that said it would send the attachments in a 'Windows friendly' way, and I think there is one on Mail ... how do I sort this in Outlook 2011?