How to attach a image on sales order communication tab

for image attachment

nlapiAttachRecord(‘file’, checkImageId, ‘salesorder’, SOId);

checkImageId is ther internalid of the image in the file cabinet

if we want to add a email on ‘message’ on communication tab

var records = new Object();

records[‘transaction’] = SOId;

var emailSend = nlapiSendEmail(senderEmailToUse, setby, emailSubject, emailBody,null,null,records);

here we need SOId is sales order internal id