21. December 2011 20:42
Wall Message attachments are one of several fun features not officially announced but in the works for v4.0. Like message images they are uploaded directly from the desktop prior to a message being posted using the simple procedure shown below. To display the attachment upload form click on the paperclip icon. After selecting your files click "Upload Files."
Your message attachments are now listed with a delete icon for removal if you change your mind.
As a side note, if you also want to upload any images with the message, those are uploaded prior to posting the message as well. Below are screenshots of the process when you're including both images and attachments with a message. There is no required order of inclusion.
Here are the results for the message demoed with both attachments and images.
Attachments are stored in /files/walls/WALLID/USERID. Attachments are displayed using a special Sueetie Wall HttpHandler to include security checks and other features. The format of stored attachment files is a 12-character length unique Guid excerpt, followed by the file extension and "attachment." Here's a screenshot.