He revisado mi código :
Código Delphi
[-]IdMessage1.ContentType := 'multipart/related; type="text/html"';
...
MessageType := 1;
IdMessage1.ContentType := 'multipart/alternative';
...
MessageType := 2;
IdMessage1.ContentType := 'multipart/mixed';
...
MessageType := 3;
IdMessage1.ContentType := 'multipart/mixed';
with TIdText.Create(IdMessage1.MessageParts, nil) do begin
ContentType := 'multipart/related; type="multipart/alternative"';
end;
with TIdText.Create(IdMessage1.MessageParts, nil) do begin
ContentType := 'multipart/alternative';
ParentPart := 0;
end;
...
MessageType := 4;
IdMessage1.ContentType := 'multipart/related; type="text/html"';
with TIdText.Create(IdMessage1.MessageParts, nil) do begin
Body.Assign(html);
ContentType := 'text/html';
if MessageType = 3 then ParentPart := 1;
CharSet := 'iso-8859-1';
end;
with TIdAttachmentFile.Create(IdMessage1.MessageParts, 'C:\AT0001.JPG') do begin
ContentID := '0001';
ContentType := 'image/jpeg';
FileName := 'AT0001.JPG';
if MessageType = 3 then ParentPart := 0;
end;
with TIdAttachmentFile.Create(IdMessage1.MessageParts, 'C:\AT0002.JPG') do begin
ContentID := '0002';
ContentType := 'image/jpeg';
FileName := 'AT0002.JPG';
if MessageType = 3 then ParentPart := 0;
end;
A ver si con estas líneas de código ya te funciona.