php - JavaBridge BIRT Send Email
The sending process doesn't have anything do to with CSS - that's entirely up to the client, though bear in mind that CSS support in email clients is extremely variable, and you can't use external style sheets. It's hard to tell because you've not shown what's in your message body.
When you say the image is broken, what do you mean?
To reference an embedded image you need to refer to its
<img src="cid:chart_image" />