Here's how to attach pictures to a post.
Attaching them to an album is the same process, but you need to be in the Album area and have created one. Then you use the "Upload Photos" button which uses the same process listed here, starting at the "Browse" step.

First, you need to be in the "Advanced" post editor. Below the text box, there is an "Additional Options" box.

Click Manage Attachments

Click browse to find the file on your computer:

If you're attaching multiple files, simply repeat the steps as necessary.

When done, click the "Close This Window" button.
Finish your post and submit it it normally -- the attachments will appear below the text.