Settings on the E-Mail tab of the Options dialog box determine what happens when you email pictures from within Picasa.
E-Mail Program. Select the email program you'll normally use when emailing photos from Picasa. When you choose File > E-Mail or click the Email button at the bottom of the Picasa window, a new email message will be created in the specified email program. All currently selected pictures will be added as message attachments. You can select your default email program, Picasa Mail (if you're a registered Hello user), or Gmail (Google email).
If you want the option to pick a different program whenever you execute the E-Mail command, click the Let me choose each time I send pictures check box.
Settings in the Output Options section determine whether pictures will be resized when sent as attachments, as well as their output format.
When sending more than one picture, resize to. Drag the slider to set the maximum image size when sending multiple attachments in a message. Only pictures larger than the specified size will be resized.
When sending single pictures, resize to. Select either the size specified for multiple pictures (the previous option) or Original Size (to prevent any single picture attachment from being resized.)
When sending movies, send. You can send the First Frame (as a single image) or the Full Movie. (However, since the point of emailing a movie is to enable the recipient to view it, you'll normally want to send the full movie.)
Send as HTML storybook (pictures only). Rather than sending pictures as attachments, you can check this option to send them embedded in the message in "storybook" format. This is an excellent option if you regularly email photos to friends and relatives who have difficulty dealing with attachments. You're free to edit any text (such as the image labels) in the Picasa-generated messages.
Note: For this option to work, you must use a standard email programnot Picasa Mail or Gmailand set that program's default message format to HTML.
This is an example of a message with photos sent as an HTML storybook.