If you are using Outlook Express, select the photos you want to send by e-mail. If you only want to send some of the photos in your file hold down the ctr key then select them individually with your mouse.
Next, right click on any of the selected photos and select "send to". Then select "mail recipient". You will now be presented with a small box asking you if you want the photos reduced(default) for e-mailing or left in full resolution. Do nothing if you want them reduced just select OK.
Outlook Express will now open up with your photos attached to an e-mail which you address and write a message and send in the usual way. Don't know if this works for other e-mail programmes.