Hello, how are you attaching the file to an email, please describe the procedure you use, your operating system version, and the mail program used.
I am using the standard Mac email client in OS X 10.9.1. I click on the attachment icon (paperclip) and select a single file from the Finder window that opens. If I select "Actual" as the file size appears to be when the two img_001122.jpg or psd files get added.
I should note that the email program only shows a single file. I only discovered that there were two files when a friend complained that he could not open a file and I went to my gmail account online and discovered the duplicate files on the server.
Is it the case only with Photoshop-generated files? try to create a JPEG in another app. and mail it.
Do you get this result every time, or just once?
It seems to be only with Photoshop generated files. It does not happen when I send files downloaded from my camera but not processed. And it does not happen necessarily every time. I haven't worked through all the variations of when it does and does not happen. I was hoping someone had a clue from a prior experience.