DTD Embedded Images
To embed non-XML data (such as an image) into your XML document, you need to treat it as an external unparsed entity. To declare an external unparsed entity, you use the <!ENTITY> declaration along with the NDATA keyword.
Syntax
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You can also use public external unparsed entities by using the PUBLIC keyword along with a Formal Public Identifier (FPI):
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Example
Here's an example of a private external unparsed entity. Here, we declare a new notation named "JPG" for the "image/jpeg" MIME type. Then we declare an external unparsed entity called "mt_cook_1" that refers to an image file called "mt_cook1_jpg". We then create a new attribute of type ENTITY - this means that we can now use this attribute in our XML document to refer to the unparsed external entity.
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After declaring the external unparsed entity in our DTD (and creating an attribute of type ENTITY), we can now embed it in our XML document:
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Embedding Multiple Images
If you need to embed multiple external unparsed entities via a single attribute, you simply give your attribute a type of ENTITIES (plural). This allows you to assign multiple images separated by a space.
Here's an example:
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Now that we've changed the "photo" attribute to type ENTITIES, we can assign multiple images to it in our XML document:
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