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I am sorry, but that is not possible to do in the Matrix field at this time.
If you will use instead the Data Grid Widget, you can add a pre-define value of URL of an image. This will only be a link to the image though, and not an embedded image.
Can you also tell us what it is you wanted to do why you need to put the images into the matrix cell? Perhaps we can offer other suggestion if we fully understand your requirement.