To post an inline image in your topic:
1. Upload the image to a web site (your own, PhotoBucket, etc)
2. Copy the link to the image from your browser's address bar
3. In your topic message, click the image icon (usually below the 'Italics' icon above the edit window) to insert BBC code for an image
4. Paste the link in between the IMG tags
5. Click Post
6. If it didn't work, then click the Modify icon (top right) and try again
To post an image as an attachment:
1. Click the "Additional Options..." link below your post (while editing)
2. To the right of the "Attach:" edit box, click the Browse button and browse to an image file to upload
3. To add more attachments, click the "(more attachments)" link and continue
Examples:
INLINE IMAGE:

ATTACHED IMAGE:
(see attachments below as thumbnails)
Brian