Hmm.
I'm confused. The A-series of paper sizes depends upon the length being equal to the width multiplied by square root of 2. You can't print out an A4 image with a size of 16 x 14 (irrespective of the chosen units) without distorting the image.
If the width is to be 14 units, the length should be 19.8 units.
If the length is fixed at 16 units, the width should only be 11.3 units.
You've also not stated what software you've got available. You may well have something suitable already (such as Photoshop or a program which came with your scanner) but I'll suggest downloading Irfanview. (It's a superb image viewing program, which also offers plenty of facilities for manipulating images):
http://www.irfanview.com/
Scan your picture, using a high resolution. (Your scanner driver might offer the chance to scan to a particular size, thus avoiding the need to use Irfanview, but I'll assume that it doesn't).
Open your image in Irfanview and press Ctrl+R (or go to Image Resize/Resample). Fill in your required dimensions and click 'OK' . Then go to File > Save As. Choose a different name for your file, so that you don't over-write the original scanned image.
You can now email the file. If the mail is rejected because the file size is too big, use a service like Uploaded.to
http://uploaded.to
and send the link to your friend.
Chris