Attaching a file to an existing thread is simple to do, but cannot be done in the quick reply section, at the bottom of the thread.
To attach a file, you must click the 'Reply' button in the top right corner of the Quick Reply section.
After you click the reply button, you will be taken to a new page with a more advanced editor. In the top right corner of that page is a button called 'Add Attachments'. Clicking this button will allow you to upload files and attach them within the thread.
Please check the FAQ'S Because we need to answer NEW questions. Asking questions that have already been answered takes time away from developing ASM into the best server manager possible.