Simple mass emailer from a Google spreadsheet. In the first sheet B2 is the subject, B3 is the body, B4 is the hml body.

emailblaster.gs

function sendEmails() {
  var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();
  var subject = sheets[0].getRange("B2").getValue();
  var textBody = sheets[0].getRange("B3").getValue();
  var logoBlob = UrlFetchApp.fetch("http://i62.tinypic.com/6emz6f.png").getBlob().setName("logoBlob"); // Replace here with your own image
  var inlineBody = sheets[0].getRange("B4").getValue();
  
  var dataRange = sheets[1].getDataRange();
  
  var data = dataRange.getValues();  
  for (var i = 0; i < data.length; i++) {
    (function(val) {
      var row = data[i];
      var emailAddress = row[0];
      Logger.log(emailAddress);
      MailApp.sendEmail(emailAddress, subject, textBody,
                    { htmlBody: inlineBody,
                      inlineImages:
                      {
                        logo: logoBlob,
                      }
                    });
      })(i);
   }
}