Thanks for your posting and using Aspose.Cells.
Since, it is an image, so if you will zoom it, then text will be shown as distorted like boxes. I have attached the output Excel file generated by your code and did not notice any considerable difference between Excel and Aspose.Cells output. Both looks same even if we zoom them.
I have attached the output I get using the code above. Why would there be such a discrepancy? I am using 188.8.131.52.
var workbook = new Workbook(“D:/temp/ChartAsPic.xlsx”);
var sheet = workbook.Worksheets;
var chart = sheet.Charts;
var ms = new MemoryStream();
sheet.Shapes.AddPicture(23, 10, ms, 100, 100);