Save the following with Applescript Editor, works with iPhoto:
on mail_images(email_subject, default_address, image_count, new_files, new_captions, new_comments, cancel_string)
try
tell application "Sparrow"
activate
set theMessage to make new outgoing message with properties {subject:email_subject, content:"Check out my sweet pictures!"}
tell theMessage
repeat with image_idx from 1 to image_count
set this_imagefile to item image_idx of new_files
set attachmentfilename to POSIX file this_imagefile
make new mail attachment with properties {filename:attachmentfilename as alias}
end repeat
compose
end tell
end tell
on error error_message number error_number
log error_message & " " & error_number
if the error_number is not -128 then
tell application "Finder"
beep
display dialog error_message buttons {cancel_string} default button 1
end tell
end if
end try
end mail_images
Save the file as Sparrow.scpt and place in: applications > iphoto > contents (right click & select show package contents) > resources > scripts
Now go to iPhoto preferences and from the dropdown menu select Sparrow (including icon!) and start mailing your pictures with Sparrow!
ps this is not my handywork. Credit goes to the original poster.