Priority Two: Instructional Materials
Adding Alternate Text to images in PDF documents
In Acrobate 8 Pro you can edit the alternate text of an image by right clicking on the image and selecting "Edit alternate text..." from the context menu.
In the dialog box that appears enter the appropriate alternate text. Note: The information must convey meaningful information. The user already knows that its an image and if they are relying on the alternate text for information just repeating that its an image is not helpful. In the case of images that contain text it is important to convey that text as well.