Within each element, certain powerpoint option can be added to specify how the element is exported

The syntax is:

"pptxOptions" : {   
        "templateKey": "template.pptx",
        "defaultSlideLayout": "slideLayout10",
        "slide": "slide4",
        "chart": 1,
        "showChartTitles": true|false
       "exportAS": "native"|"image",
"transform":{
     "x": "3.0in",
     "y": "4.5in"
}
}