PSE 18 will not open pictures

My friend took some pictures for me and when I tried to open them in PSE 18 I received the following message.  "Cannot complete request because it is not the right kind of document.  She used a Pink Nicon S01.  When the pictures showed up in my email as an attachment all I could see was a gray box with a paperclip in it. Also tried to open them in Microsoft Office Picture Manager with no success.  They will open in Windows Photo Viewer but I am not able to safe them.  They do not have a .jpg extension after their number which looks like this .. DSCN5759 (1).  Also, when searching for a program to open these pictures at the top of the box is the following wording ... "Application/Octet-stream"  How can I get these pictures opened/saved.

Thanks...Joan Nasiatka  jcnpeanuts@yahoo.com