does not sent ALERT mail with smtp due to problem with images

Because the problem could not be reproduced, including the large size graphs (>50K) and over smtp server provided by the user. Probably a problem in the user os environment.

I did some more test and I can confim that:
1) email smaller than 20K works correctly
2) email larger than 20K does not works (even if I use an smtp postfix on localhost)
3) the problem is on th smtp session between the php and the configured smtp server
4) if I use "sendmail" instead of "smtp" as transport protocol it works correctly even with mail bigger than 20K

No, mime parts already wrapped by 76 chars as in pear Mail:Mime:
// RFC2822 recommends 78 characters limit, use 76 from RFC2047

and graphs included not as mime part, but as data-uri.

the problem may be int the php not wordwrapping to 70 char per line mime attach?

ya, Emilio, I'm got your email, thanks.

hello mike, I did sent you the debug to your email address (our company policy does not allow me to publish on the public internet details on our network layout without an approval from managemenet);

Test mail works perfectly and also work perfectly all the email smaller than 20K... the problem is with mail larger than 20K (I can receive alert mail with graph embedded, if the size is smaller than 20K and I receive all the RECOVER mail without graph attached, as they are always smaller than 20K)

please show me debug out from script:
./test_mail.ph -d -h <some host>

no, it's not fixed... the smtp transaction when there is a graph attached end with this:

KMwv7I0MD481GA3Ys28v5qSn//A/b9zxia/r5wvk5ZXrBULBjeULFxe5yqdSq3GkrdVYVlzGUMT=
5q0kex2h1WjQe2AQUIT

while it should end with
.
QUIT

(actually it's missing also the end of the mail, if I correctly read the php generating the mail)

Please try latest commit, should be fixed

this is the configuration:
$config['email_backend'] = 'smtp';
$config['email_from'] = 'observium@XXXXXX.it';
$config['email_smtp_host'] = 'smtp-int.dc.XXXXXXX.it'; // Outgoing SMTP server name.
$config['email_smtp_port'] = 25; // The port to connect.
$config['email_smtp_timeout'] = 10; // SMTP connection timeout in seconds.

and I found the problem in the ALERT email (not the RECOVER email, which does not have the image) sent by alert checker with conditions like "ifInOctets_perc gt 90 and ifOutOctets_perc gt 90"
if you need them I send you (in private) the pcap captured on the smtp server