To provide alternate text for an image in DITA, you need an <alt> tag. Instead of using a GraphAlt marker, which causes the content to become an attribute, you have to insert the text via the FrameMaker Object Attributes dialog for the anchored frame; see §29.4.2 . Mif2Go produces <alt> tags if and only if you use the FrameMaker Object Attributes dialog. Place the text in the Alternate: box under Text Attributes. Do not place the text in the Defined Attributes: box under New or Changed Attribute; if you do, the content will become the attribute, which is deprecated for DITA.