A method, system, and computer-readable medium are provided for determining whether to reproduce a chart image from the contents of a spreadsheet application workbook on a server. A calculation server calculates chart data for defining a chart image from workbook data retrieved from the spreadsheet application workbook, generates a representation of the chart data, and calculates an identifier for the representation of the chart data. A charting component receives the representation of the chart data and the identifier from the calculation server and compares the calculated identifier to a previously stored identifier on the server. If the calculated identifier is equal to the previously stored identifier, then the charting component retrieves a previously produced chart image from the representation of the chart data from the server. If the calculated identifier is not equal to the previously stored identifier, then the charting component produces a chart image from the representation of the chart data.