I cannot retrieve either video clips or Jpegs of photos on my iPad. The appropriate settings are on. All I get is "winmail.dat" and the instruction that 'Mail cannot open this attachment'Jpegs
It has to do with the settings on the originating mail client; and how it is handling attachments. Make sure the originator is sending attachments with the full file name and extension (mypicture.jpg)
No modern email client should still be sending attachments this way. Other than that, I can't really help you. Sorry.