Why defects in photos transmitted by e-mail?

Question

Recently I sent six photos to a friend via Apple Mail. These photos were stored in iPhoto. I sent each photo individually by highlighting it and then clicking on the Email icon at the bottom of the page. The size selected was Actual Size (Full Quality), after which I clicked the Compose button and sent the photos to the designated recipient.
What I was dismayed to discover was that two of the six transmitted photo copies had defects that were not present in the original photos. One transmitted photo showed objectionable noise that was not present in the original. (The photo was shot with a Nikon D200 at ISO 3200, but Noise Ninja was very effective in producing a clean noise-free image). The second photo, which pictured supporting cables for a suspension bridge, showed dashed, wavy, or stair-step patterns in the cables in the transmitted copy whereas the cables in the original photo were solid black lines with no such patterns at all. It appears that the process for setting up the photos for e-mailng was responsible for producing these defects in the transmitted copies.
I would greatly appreciate having some knowledgeable person explain to me what is going on here and what can be done to prevent it from happening. If possible I would like to re-transmit those two photos via e-mail without having the defects show up.
Bob

Answer 1

To get around any issues with emailing photos compress them and send. By compress I mean put them in a folder and the Control-click on the folder and select the Compress "folder" option. The attach the zip file to the email.
TIP: For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto (iPhoto.Library for iPhoto 5 and earlier) database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've created an Automator workflow application (requires Tiger or later), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 6 and 7 libraries and Tiger and Leopard. iPhoto does not have to be closed to run the application, just idle. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.