By default, the PictureAspectRatioNode property is exAspectRatioNone. If the PictureAspectRatioNode property is set, it is applied to all nodes, excepts where the node's PictureAspectRatio is being set. In other words, you can use the PictureAspectRatioNode property to apply the same aspect ratio for all pictures in the chart. If using the PictureAspectRatio property you can use the PictureWidthNode or PictureHeightNode property to specify the fixed width or height for the picture. Use the Picture property to specify the node's picture. 

The aspect ratio for the node's picture works as follows:

• exAspectRatioWidth,  the PictureWidth or PictureWidthNode property must specify the fixed width, so the height of the displaying picture is calculated based on the original size, so it keeps its aspect ratio.
• exAspectRatioHeight,  the PictureHeight or PictureHeightNode property must specify the fixed height, so the width of the displaying picture is calculated based on the original size, so it keeps its aspect ratio.

The size of the picture being shown in the node is computed as follow:

• if the PictureWidth and/or PictureHeight property is specified, it indicates the width or the height of the picture being shown in the node.
• if the PictureWidthNode and/or PictureHeightNode properties of the ChartView object is specified, it indicates the width or the height of the picture being shown in the node.
• If none of these is specified, the node displays the picture using its size.

In any case, the size of the picture is also influenced by the the aspect ratio for the node's picture as it is specified by PictureAspectRatio or PictureAspectRatioNode property while any of these is not exAspectRatioNone.