This sounds like a great candidate for a Component Action on the Chart component — so that you could have a button which lets you declaratively capture the chart as a PDF / JPEG and then allow you to store it to the locations that we support for the File Upload component, e.g. for Salesforce, attachments / content documents / etc. Would also be great to be able to just initiate the download using your own custom buttons instead of relying on the user to click the icon.
