Hi,
define display callback and just return proper value with image
public static function display_your_field($record, $nolink, $desc) {
$img = '<img src="'. Base_ThemeCommon::get_template_file('Custom/YourModule', 'image.png') . '">';
return $img . $record[$desc['id']];
}
You have to install theme within install method in YourModuleInstall.php file.
Base_ThemeCommon::install_default_theme('Custom/YourModule');
your image file has to be here: modules/Custom/YourModule/theme/image.png
before calling install default theme.
If you want to change image then replace this file (modules/Custom/YourModule/theme/image.png)
and run "Theme up" from /admin tools, and probably clear browser's cache.
Regards,
Adam