Adding a picture to place holder on a PowerPoint slide

Hello,

I am trying to automate the creation of a presentation during an
analysis run from Matlab. The idea is to generate some analysis numbers
and a plot for each step, and add the details programmatically to a
PowerPoint slide.

At the beginning of the run, the user opens a blank new presentation
which captures all the output sent by osascript called by Matlab with
command line arguments constructed by matlab (one title, two text items
and one image file). Please do not worry about how Matlab does all
that. I know how to do that part pretty well. The issue is an
AppleScript issue purely.

I have selected a two column layout (text box and picture). When I run
the script below without the picture, I get what I expect (a title and
two items in the text box).

I cannot figure out how to set the content of the third placeholder
with the image file the way I am creating the text box (see below).

--------

set thePicturePath to POSIX file (ImageFile)

tell application "Microsoft PowerPoint"
tell active presentation
set sObj to make new slide at end with properties {layout:slide
layout text and object}
set content of text range of text frame of place holder 1 of sObj
to theTitle
set content of text range of text frame of place holder 2 of sObj
to listItem1 & return & listItem2
??
end tell
end tell

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So, how do I add an image to place holder 3 in the "??" above ?

Thanks.