Click Use advanced editor link (top right corner of Reply window).
Then click Attach link (bottom right corner of Reply window).
Select the file.
Scroll down to the bottom of the web page.
Click Add Reply button.
Click Use advanced editor link (top right corner of Reply window).
Then click Attach link (bottom right corner of Reply window).
Select the file.
Scroll down to the bottom of the web page.
Click Add Reply button.