Make your text body, when you're ready to add the pic(s) then do this..
1) click on manage attachments
2) you will see two boxes one will be labeled upload file from your computer
3) Click on browse next to it
4) navigate to your pic or pics you want to add..one at a time
5)select the file
6) click on upload file
as long as you are under the size limits you will be okay and good to go