Can't send attachments with mail.app

Hello friends. I am using a mac book pro "17 version 10.7.4

I can't send e-mails which inludes attachments qith mail.app in gmail account.

I can send the same e-mail if I choose hotmail account. Also Gmail works fine with browser.

However sending attachments are problem with gmail account in mail.app

Does anybody knows why is that and how can I fix that?

Waiting for replies.

Thanks.
Cagri

What sort of attachments, is is just that images are appearing inline rather than as attachment icons

no it doesn't send messages if it has a little bit big attachments. I mean like 1 or 1.5 mb.

It gives error and tells me to select another server to send it. Hotmail doesn't do that but gmail account does this.

Hotmail is pop

gmail is imap

is this the reason?