Introduction

try {
    // Get the text pane's document
    JTextPane textPane = new JTextPane();
    StyledDocument doc = (StyledDocument)textPane.getDocument();

    // The image must first be wrapped in a style
    Style style = doc.addStyle("StyleName", null);
    StyleConstants.setIcon(style, new ImageIcon("imagefile"));

    // Insert the image at the end of the text
    doc.insertString(doc.getLength(), "ignored text", style);
} catch (BadLocationException e) {
}