[horde] Problem with size of attachment

[Betty Kakali]

I have a problem with sending attachments using WebMail. When the attachment is bigger than 1 MB I get the message
"Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 1783796 bytes) in /usr/share/horde/imp/compose.php3 on line 684"
I have already tried the solution you suggest (increasing the max_upload_size in php.ini) but did'nt work.
Besides the max_upload_size was 2 MB and I was trying to send an attachment of 1.3 MB.
What should I do???
 (IMP Version 2.2.6)

Thank you in advance.