If you have a desktop tool like outlook or thunderbird the easier solution is to drag-drop the files you want from xplorer² into the email composition window. They will be attached and sent as part of the email to your recipient.
If you don't have your email client program running, you can right click on the documents you need emailed, and pick the Mail recipient command from Send To shell context menu. As a result your email program will start and offer you a blank email with the selected files attached. Just add your message and recipient email addresses and you are all set. When you send pictures this way the Mail recipient applet will offer to reduce the picture size before delivery.
If you send too many emails with attachments you can simplify your life adding the Mail recipient applet as a drop target in the miniscrap pane. Then you can drag-drop files inside xplorer² and have them emailed just as if you used the context menu. I don't know how much objective improvement this would be but it has a definite novely value :)