I think your best bet is to upload that photo to a cloud storage account. Many are free such as Dropbox or Photobucket (tho Photobucket is only for photos).
Then, with the photo safely in the cloud, the service will have a way to create a link to that photo. Once you have the link, you can then e-mail it for the other person to click on and be taken to where that picture is.
It makes it much easier to share photos with others as (1) they don't get their inboxes bogged down with photos and (2) they can always browse the photo(s) at their leisure.