How do I add style to images?

[fyy623]

Basically, I want to achieve "Format Picture" in Office Word, where you right click an element in a .docx file and attach solid line (ideally, I want to also manually set color, width, transparency, etc) border to the image

import docx
from docx import Document
from docx.oxml import OxmlElement
from docx.oxml.ns import qn
doc = Document(p)
for element in doc.element.body:
    if hasattr(element, 'inner_content_elements'):
        for ele in element.inner_content_elements:
            for i in ele.inner_content_items:
                outline = OxmlElement('a:ln', {'w': '9525'})
                solid_fill = OxmlElement('a:solidFill')
                scheme_color = OxmlElement('a:schemeClr', {'val': 'green'})
                solid_fill.append(scheme_color)
                outline.append(solid_fill)
                i.append(outline)

Above is the code I tried, which gives no error, but the result file is broken, as it says when I tried to open the file:

Word experienced an error trying to open the file. 
Try these suggestions.
* Check the file permissions for the document or drive.
* Make sure there is sufficient free memory and disk space.
* Open the file with the Text Recovery converter.
(Path/to/the/file)

Any suggestions?