You can use Picasa 2 to send pictures from most popular email programs, such as Outlook, Outlook Express, AOL, and Thunderbird.
To send pictures with your Default Email program:
1. Select the pictures you want to send, and click the Email button.
2. Choose the top option, which should show the name of your email program
3. Enter a destination email address, subject, and message.
4. When you are finished, send your message.
Picasa 2 works with most MAPI compliant email programs.
Learn how to set picture size and more in Email Options.