code: protected AbstractColumn buildSimpleImageColumn() {
  		ImageColumn column = new ImageColumn();
  		populateCommonAttributes(column);
  		populateExpressionAttributes(column);
  		
  		column.setExpression(customExpression);
  		column.setExpressionToGroupBy(customExpressionToGroupBy);
  		column.setExpressionForCalculation(customExpressionForCalculation);
  		
  		column.setScaleMode(imageScaleMode);
  		return column;
  	}
docs: When creating image columns
  @return