MS Outlook is “shrinking “text” when forwarding/reply is clicked on…

My MS..XP Outlook is shrinking the mail text when the forwarding or reply options are used…The text regains size at other end …but the immediate reaction to the forward command is a reduction of 1000% of the on screen text size…..I had previously been re-sizing image inserts in Outlook mail and I suspect that the reduction has been made the default size for everything….Help please…