How to display image on Button in SwiXML at runtime

Hi,
I am using SwiXML and using table.
I am preparing table's model using following code.
I am adding

Object[][] tableData = new Object[rows][columns + extraColumns];
for(int i=0; i<rows; i++){
  for(int j=0; j<columns; j++){
	  tableData[i][j] = d[i][j];//d[][] already contains some data
  }
  tableData[i][columns] = new JButton(new ImageIcon("edit.gif"));//Edit
  tableData[i][columns+1] = new JButton(new ImageIcon("view.gif"));//View
  tableData[i][columns+2] = new Boolean(false);//Delete check box
}

I am wondering that the edit and view buttons get displayed without any
image. There is not location or path not found issue for images.
Even, If I don't use image and just say new JButton("Edit"), it doesn't
display the button text.

Can anyone tell me where am I wrong?
Is this the correct way to create model in order to display images on button
in SwiXML?

Thanks.
Bharat