Unsigned applets can't access the system clipboard, so use javax.jnlp.ClipboardService
and create jar/jnlp file.
PasteImageApplet.java
try {
ClipboardService cs =
(ClipboardService)ServiceManager.lookup("javax.jnlp.ClipboardService");
img = (Image)cs.getContents().getTransferData(DataFlavor.imageFlavor);
} catch (Exception ex) {
}
PasteImage.jnlp
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.6+" href="PasteImage.jnlp">
<information>
<title>Paste Image</title>
<vendor>ABC</vendor>
</information>
<resources>
<java version="1.6+"
href="http://java.sun.com/products/autodl/j2se" />
<jar href="PasteImage.jar" main="true"/>
</resources>
<applet-desc name="PasteImage"
main-class="PasteImageApplet"
width="320" height="120">
</applet-desc>
index.html
<applet width="320" height="120">
<param name="jnlp_href" value="PasteImage.jnlp" />
</applet>