Office Script to add image

Hi! I am using the following code to add image into excel sheet automatically. However, it only works for JPG file and not for JPEG and PNG file. May I modify the following code and let it works for 3 types of image files? Thank you very much.

function main(workbook: ExcelScript.Workbook, base64ImageString: string,imageName: string) {
  // get table row count
  let sheet1 = workbook.getWorksheet('In progress');
  let table1 = workbook.getTable('Inprogress');
  
  let rowCount = table1.getRowCount();
  let n1:number = rowCount + 1;
  let range1:string = '';
  let imageAddress:string = '';
  let nameAddress:string = '';

  imageAddress = 'J' + n1.toString();
  nameAddress = 'N' + n1.toString();
  range1 = n1 + ':' + n1

  sheet1.getRange(range1).getFormat().setRowHeight(230);

  let range = sheet1.getRange(imageAddress);
  let image = sheet1.addImage(base64ImageString);
  image.setName(imageName);
  image.setTop(range.getTop());
  image.setLeft(range.getLeft());
  image.setWidth(300);
  image.setHeight(225);

  sheet1.getRange(nameAddress).setValue(imageName)
}