I downloaded your plugin. it works great, but i found that the size of the popup is fixed at 800px (width) and 650px (height).
I'm not a developer, but i found that this values are recorded and readed from the wordpress database, so i added some lines of code in setting_page.php, after "Popup Image" title, to be able to change them.
<tr valign="top"> <td>Popup Image Size</td> <td> <p><input type="text" name="arty_settings[popup_width]" id="popup_width" size="3" value="<?php echo $options['popup_width']; ?>"> Width of the image</p> <p><input type="text" name="arty_settings[popup_height]" id="popup_height" size="3" value="<?php echo $options['popup_height']; ?>"> Height of the image</p> </td> </tr>
I hope you can add this code (or a better one) to the official version.
Have a nice day!