<w:drawing>
    <wp:inline>
        <wp:extent cx="3297600" cy="2782800"/>
        <wp:effectExtent l="0" t="0" r="0" b="0"/>
        <wp:docPr id="1" name="Picture 1"/>
        <wp:cNvGraphicFramePr>
            <a:graphicFrameLocks/>
        </wp:cNvGraphicFramePr>
        <a:graphic>
            <a:graphicData>
                <pic:pic>
                    <!-- more pic content -->
                </pic:pic>
            </a:graphicData>
        </a:graphic>
    </wp:inline>
</w:drawing>

<w:drawing>
    <wp:anchor behindDoc="1" locked="0" layoutInCell="1" allowOverlap="1">
        <wp:simplePos x="0" y="0"/>
        <wp:positionH relativeFrom="page">
            <wp:posOffset>285750</wp:posOffset>
        </wp:positionH>
        <wp:positionV relativeFrom="page">
            <wp:posOffset>457200</wp:posOffset>
        </wp:positionV>
        <wp:extent cx="3297600" cy="2782800"/>
        <wp:effectExtent l="0" t="0" r="0" b="0"/>
        <wp:wrapNone/>
        <wp:docPr id="1" name="Picture 1"/>
        <wp:cNvGraphicFramePr>
            <a:graphicFrameLocks/>
        </wp:cNvGraphicFramePr>
        <a:graphic>
            <a:graphicData>
                <pic:pic>
                    <!-- more pic content -->
                </pic:pic>
            </a:graphicData>
        </a:graphic>
    </wp:anchor>
</w:drawing>

from docx import Document
from docx.shared import Pt
 
document = Document()
document.add_picture('image.jpg', width=Pt(200))
document.save('output.docx')

def add_picture(self, image_path_or_stream, width=None, height=None):
    inline = self.part.new_pic_inline(image_path_or_stream, width, height)
    self._r.add_drawing(inline)
    return InlineShape(inline)

def new_pic_inline(self, image_descriptor, width, height):
    """Return a newly-created `w:inline` element.
    The element contains the image specified by *image_descriptor* and is scaled
    based on the values of *width* and *height*.
    """
    rId, image = self.get_or_add_image(image_descriptor)
    cx, cy = image.scaled_dimensions(width, height)
    shape_id, filename = self.next_id, image.filename
    return CT_Inline.new_pic_inline(shape_id, rId, filename, cx, cy)

class CT_Inline(BaseOxmlElement):
    """
    ``<w:inline>`` element, container for an inline shape.
    """
    @classmethod
    def new(cls, cx, cy, shape_id, pic):
        pass
 
    @classmethod
    def new_pic_inline(cls, shape_id, rId, filename, cx, cy):
        pass
 
    @classmethod
    def _inline_xml(cls):
        return (
            '<wp:inline %s>\n'
            '  <wp:extent cx="914400" cy="914400"/>\n'
            '  <wp:docPr id="666" name="unnamed"/>\n'
            '  <wp:cNvGraphicFramePr>\n'
            '    <a:graphicFrameLocks noChangeAspect="1"/>\n'
            '  </wp:cNvGraphicFramePr>\n'
            '  <a:graphic>\n'
            '    <a:graphicData uri="URI not set"/>\n'
            '  </a:graphic>\n'
            '</wp:inline>' % nsdecls('wp', 'a', 'pic', 'r')
        )

# docx.oxml.__init__.py
register_element_cls('wp:inline', CT_Inline)

# -*- coding: utf-8 -*-
 
# filename: add_float_picture.py
 
'''
Implement floating image based on python-docx.
- Text wrapping style: BEHIND TEXT <wp:anchor behindDoc="1">
- Picture position: top-left corner of PAGE `<wp:positionH relativeFrom="page">`.
Create a docx sample (Layout | Positions | More Layout Options) and explore the 
source xml (Open as a zip | word | document.xml) to implement other text wrapping
styles and position modes per `CT_Anchor._anchor_xml()`.
'''
 
from docx.oxml import parse_xml, register_element_cls
from docx.oxml.ns import nsdecls
from docx.oxml.shape import CT_Picture
from docx.oxml.xmlchemy import BaseOxmlElement, OneAndOnlyOne
 
# refer to docx.oxml.shape.CT_Inline
class CT_Anchor(BaseOxmlElement):
    """
    ``<w:anchor>`` element, container for a floating image.
    """
    extent = OneAndOnlyOne('wp:extent')
    docPr = OneAndOnlyOne('wp:docPr')
    graphic = OneAndOnlyOne('a:graphic')
 
    @classmethod
    def new(cls, cx, cy, shape_id, pic, pos_x, pos_y):
        """
        Return a new ``<wp:anchor>`` element populated with the values passed
        as parameters.
        """
        anchor = parse_xml(cls._anchor_xml(pos_x, pos_y))
        anchor.extent.cx = cx
        anchor.extent.cy = cy
        anchor.docPr.id = shape_id
        anchor.docPr.name = 'Picture %d' % shape_id
        anchor.graphic.graphicData.uri = (
            'http://schemas.openxmlformats.org/drawingml/2006/picture'
        )
        anchor.graphic.graphicData._insert_pic(pic)
        return anchor
 
    @classmethod
    def new_pic_anchor(cls, shape_id, rId, filename, cx, cy, pos_x, pos_y):
        """
        Return a new `wp:anchor` element containing the `pic:pic` element
        specified by the argument values.
        """
        pic_id = 0  # Word doesn't seem to use this, but does not omit it
        pic = CT_Picture.new(pic_id, filename, rId, cx, cy)
        anchor = cls.new(cx, cy, shape_id, pic, pos_x, pos_y)
        anchor.graphic.graphicData._insert_pic(pic)
        return anchor
    @classmethod
    def _anchor_xml(cls, pos_x, pos_y):
        return (
            '<wp:anchor distT="0" distB="0" distL="0" distR="0" simplePos="0" relativeHeight="0" \n'
            '           behindDoc="1" locked="0" layoutInCell="1" allowOverlap="1" \n'
            '           %s>\n'
            '  <wp:simplePos x="0" y="0"/>\n'
            '  <wp:positionH relativeFrom="page">\n'
            '    <wp:posOffset>%d</wp:posOffset>\n'
            '  </wp:positionH>\n'
            '  <wp:positionV relativeFrom="page">\n'
            '    <wp:posOffset>%d</wp:posOffset>\n'
            '  </wp:positionV>\n'                    
            '  <wp:extent cx="914400" cy="914400"/>\n'
            '  <wp:wrapNone/>\n'
            '  <wp:docPr id="666" name="unnamed"/>\n'
            '  <wp:cNvGraphicFramePr>\n'
            '    <a:graphicFrameLocks noChangeAspect="1"/>\n'
            '  </wp:cNvGraphicFramePr>\n'
            '  <a:graphic>\n'
            '    <a:graphicData uri="URI not set"/>\n'
            '  </a:graphic>\n'
            '</wp:anchor>' % ( nsdecls('wp', 'a', 'pic', 'r'), int(pos_x), int(pos_y) )
        )
# refer to docx.parts.story.BaseStoryPart.new_pic_inline
def new_pic_anchor(part, image_descriptor, width, height, pos_x, pos_y):
    """Return a newly-created `w:anchor` element.
    The element contains the image specified by *image_descriptor* and is scaled
    based on the values of *width* and *height*.
    """
    rId, image = part.get_or_add_image(image_descriptor)
    cx, cy = image.scaled_dimensions(width, height)
    shape_id, filename = part.next_id, image.filename    
    return CT_Anchor.new_pic_anchor(shape_id, rId, filename, cx, cy, pos_x, pos_y)
# refer to docx.text.run.add_picture
def add_float_picture(p, image_path_or_stream, width=None, height=None, pos_x=0, pos_y=0):
    """Add float picture at fixed position `pos_x` and `pos_y` to the top-left point of page.
    """
    run = p.add_run()
    anchor = new_pic_anchor(run.part, image_path_or_stream, width, height, pos_x, pos_y)
    run._r.add_drawing(anchor)
# refer to docx.oxml.__init__.py
register_element_cls('wp:anchor', CT_Anchor)

from docx import Document
from docx.shared import Inches, Pt
from add_float_picture import add_float_picture
 
if __name__ == '__main__':
 
    document = Document()
 
    # add a floating picture
    p = document.add_paragraph()
    add_float_picture(p, 'test.png', width=Inches(5.0), pos_x=Pt(20), pos_y=Pt(30))
 
    # add text
    p.add_run('Hello World '*50)
 
    document.save('output.docx')