Use the Size element to scale map shapes according to the size variable, minimizing distortion.
Example of SAT.jmp After Dragging Population to Size
3.
You can also change the transparency of images (for example, Simple Earth and Detailed Earth). To set the transparency, right-click over the graph and select Customize.... This brings up the Customize Graph window, where you can select the Background Map and assign a value for transparency. A valid value for transparency goes from 0.0 (completely transparent) to 1.0 (completely opaque). Within Graph Builder, you can also right-click over the graph and select Graph > Transparency.
Right-click Menu for Graphics
Customize - You can change the properties of the graph such as contents, grid lines, or reference lines. The graphical elements that you can customize differ for each graph. Select Background Map to change the transparency of a background map or Map Shape to change the line color, line style and width, fill color, missing shape fill or missing value fill. Click Help in the Customize Graph window for a more detailed explanation of the customize options.

Help created on 9/19/2017