Powerpoint 2013: Converting Equations to Images

Hello,

I would like to convert the equations in a Powerpoint 2013 presentation to images in order to avoid compatibility issues. I have tried to write a macro using VBA, but I am not sure how to identify the Equations themselves. My code so far:

Sub EquationToImage()

    For Each slid In ActivePresentation.Slides
        For Each shap In SlideToCheck.Shapes
            If shap.HasTextFrame Then              
???
???
        Next
    Next
End Sub

I was expecting to find Equations in the TextFrame object. Are they stored as text? How could I identify Equations and, for instance, use CopyAsPicture on them exclusively?

Thank you for any help you can provide!