Save my time & bandwidth: Think before replying in HTML

I get in tons of emails the following text appended to the sender’s signature (or similar):
Save a tree: Think before you print this email

Usually, that text is included along with some big JPEG image included within an HTML-formatted colourful email, which of course, takes its time to render in my email desktop application or even worse, shown as attached image in GMail interface.

Now I am thinking in adding this other text after my signature in the emails:
Save my time & bandwidth: Think before you reply to this email in HTML