Park Kraken:Use the 'Post Reply' image link, or 'Go Advanced' button beneath the Quick Reply box.
How do you host, or upload, modified maps again? I've made my appropriate changes.
Scroll down to the 'Additional Options' section. You may have to expand it. There is a form field titled 'Attack Files' there, click the 'Manage Attachments' button to open a popup that will let you upload images and files.