I use this code import arcpy mxd = arcpy.mapping.MapDocument("CURRENT") df = arcpy.mapping.ListDataFrames(mxd)[0] ar = df.extent.height / df.extent.width arcpy.mapping.ExportToPNG(mxd,r"C:\Users\Kakemphaton\Desktop\out.png",df,1024,1024*ar,96,True) to export a dataframe to png, it works.

Code from : Writing world file when exporting TIFF using ArcPy Mapping?

This code export only the first dataframe and always the first. I can't export others

But, i have multiple data frames in my mxd (exemple_1, exemple_2, example_3), my wish export the three dataframes, the previous code export only example_1. How i could export example_2 and example_3, i tried to activate for example example_2, but esri export always example_1.

Thanks