First, in the Library module, navigate to the image (or images, by control-clicking to select multiple images) you’d like to send, then click on the File drop-down menu and look for the Email Photo command about halfway down. Click Email Photo and a dialogue box will open up.
The first time you go to email a photo you’ll have to input your email account information into Lightroom. Simply give your account a name and choose the account type from the drop-down menu. Next, you’ll input your email address and credentials (i.e. your password) just as you would when setting up an email account on a new computer or your mobile phone. (In fact, I use my mobile phone’s account settings as a cheat sheet for the specific email account settings.) With the account details in place, click Okay. Lightroom will validate the email account settings before allowing you to proceed.
From this point forward, any time you click Email Photo in the File Menu (or use the Command-Shift-M shortcut key) you’ll be taken directly to a new email message popup window. From here, it’s largely the same process as composing any new message in any email application. You’ll input the destination email address and subject, you can change the font and formatting of your message as well, and then you can type in your message. Lastly, before you hit Send, you can see the thumbnail preview of the selected image near the bottom of the frame, and you can change the size of that image file by choosing one of your existing export presets, or you can create a new preset in order to specify the file type, dimensions, sharpening, compression and file name that you’d like to use. Once you’ve got the right output specifications set, simply click Send and the message will be delivered. I wouldn’t try sending huge image files this way, but for small files destined for the internet, or simply those that you want to share if not print, this is a quick and easy way to email images all in one application.