Word allows a graphical object to be placed into a document as an inline object. An inline shape appears as a <w:drawing> element as a child of a <w:r> element.
The following interactive session illustrates the protocol for accessing an inline shape:
>>> inline_shapes = document.body.inline_shapes
>>> inline_shape = inline_shapes[0]
>>> assert inline_shape.type == MSO_SHAPE_TYPE.PICTURE
The Shapes and InlineShapes properties on Document hold references to things like pictures in the MS API.
This XML represents my best guess of the minimal inline shape container that Word will load:
<w:r>
<w:drawing>
<wp:inline>
<wp:extent cx="914400" cy="914400"/>
<wp:docPr id="1" name="Picture 1"/>
<a:graphic xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main">
<a:graphicData uri="http://schemas.openxmlformats.org/drawingml/2006/picture">
<!-- might not have to put anything here for a start -->
</a:graphicData>
</a:graphic>
</wp:inline>
</w:drawing>
</w:r>
A CT_Drawing (<w:drawing>) element can appear in a run, as a peer of, for example, a <w:t> element. This element contains a DrawingML object. WordprocessingML drawings are discussed in section 20.4 of the ISO/IEC spec.
This XML represents an inline shape inserted inline on a paragraph by itself. The particulars of the graphical object itself are redacted:
<w:p>
<w:r>
<w:rPr/>
<w:noProof/>
</w:rPr>
<w:drawing>
<wp:inline distT="0" distB="0" distL="0" distR="0" wp14:anchorId="1BDE1558" wp14:editId="31E593BB">
<wp:extent cx="859536" cy="343814"/>
<wp:effectExtent l="0" t="0" r="4445" b="12065"/>
<wp:docPr id="1" name="Picture 1"/>
<wp:cNvGraphicFramePr>
<a:graphicFrameLocks xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main" noChangeAspect="1"/>
</wp:cNvGraphicFramePr>
<a:graphic xmlns:a="http://schemas.openxmlformats.org/drawingml/2006/main">
<a:graphicData uri="http://schemas.openxmlformats.org/drawingml/2006/picture">
<!-- graphical object, such as pic:pic, goes here -->
</a:graphicData>
</a:graphic>
</wp:inline>
</w:drawing>
</w:r>
</w:p>
<xsd:complexType name="CT_Drawing">
<xsd:choice minOccurs="1" maxOccurs="unbounded">
<xsd:element ref="wp:anchor" minOccurs="0"/>
<xsd:element ref="wp:inline" minOccurs="0"/>
</xsd:choice>
</xsd:complexType>
<xsd:complexType name="CT_Inline">
<xsd:sequence>
<xsd:element name="extent" type="a:CT_PositiveSize2D"/>
<xsd:element name="effectExtent" type="CT_EffectExtent" minOccurs="0"/>
<xsd:element name="docPr" type="a:CT_NonVisualDrawingProps"/>
<xsd:element name="cNvGraphicFramePr" type="a:CT_NonVisualGraphicFrameProperties" minOccurs="0"/>
<xsd:element name="graphic" type="CT_GraphicalObject"/>
</xsd:sequence>
<xsd:attribute name="distT" type="ST_WrapDistance"/>
<xsd:attribute name="distB" type="ST_WrapDistance"/>
<xsd:attribute name="distL" type="ST_WrapDistance"/>
<xsd:attribute name="distR" type="ST_WrapDistance"/>
</xsd:complexType>
<xsd:complexType name="CT_PositiveSize2D">
<xsd:attribute name="cx" type="ST_PositiveCoordinate" use="required"/>
<xsd:attribute name="cy" type="ST_PositiveCoordinate" use="required"/>
</xsd:complexType>
<xsd:complexType name="CT_EffectExtent">
<xsd:attribute name="l" type="a:ST_Coordinate" use="required"/>
<xsd:attribute name="t" type="a:ST_Coordinate" use="required"/>
<xsd:attribute name="r" type="a:ST_Coordinate" use="required"/>
<xsd:attribute name="b" type="a:ST_Coordinate" use="required"/>
</xsd:complexType>
<xsd:complexType name="CT_NonVisualDrawingProps">
<xsd:sequence>
<xsd:element name="hlinkClick" type="CT_Hyperlink" minOccurs="0"/>
<xsd:element name="hlinkHover" type="CT_Hyperlink" minOccurs="0"/>
<xsd:element name="extLst" type="CT_OfficeArtExtensionList" minOccurs="0"/>
</xsd:sequence>
<xsd:attribute name="id" type="ST_DrawingElementId" use="required"/>
<xsd:attribute name="name" type="xsd:string" use="required"/>
<xsd:attribute name="descr" type="xsd:string" default=""/>
<xsd:attribute name="hidden" type="xsd:boolean" default="false"/>
<xsd:attribute name="title" type="xsd:string" default=""/>
</xsd:complexType>
<xsd:complexType name="CT_NonVisualGraphicFrameProperties">
<xsd:sequence>
<xsd:element name="graphicFrameLocks" type="CT_GraphicalObjectFrameLocking" minOccurs="0"/>
<xsd:element name="extLst" type="CT_OfficeArtExtensionList" minOccurs="0"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="CT_GraphicalObject">
<xsd:sequence>
<xsd:element name="graphicData" type="CT_GraphicalObjectData"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="CT_GraphicalObjectData">
<xsd:sequence>
<xsd:any minOccurs="0" maxOccurs="unbounded" processContents="strict"/>
</xsd:sequence>
<xsd:attribute name="uri" type="xsd:token" use="required"/>
</xsd:complexType>