--- imagefield_crop.install	2009-01-29 12:12:10.000000000 +0200
+++ imagefield_cropNEW.install	2009-08-26 21:47:14.000000000 +0300
@@ -19,4 +19,20 @@ function imagefield_crop_update_6000() {
   content_clear_type_cache(TRUE);
 
   return $ret;
-}
\ No newline at end of file
+}
+
+/**
+ * implementation of hook_enable
+ * we want to make sure that this module is enabled only when not only imageapi is enabled (this module dependancies take care of 
+ * that), but also when at least one of its toolkits (GD, imagemagick) are enabled as well.
+ * @see http://drupal.org/node/466948 (this function resolves it)
+ * 
+ * @return void
+ */
+function imagefield_crop_enable() {
+    if (count(imageapi_get_available_toolkits()) == 0) {
+        drupal_set_message(t('Image Crop module requires that at least one imageapi toolkit is enabled. Please enable it in !modules and try again. Disabling Image Crop for now.', 
+        array('!modules' => l('admin/build/modules', 'admin/build/modules'))), "error");
+        module_disable(array("imagefield_crop"));
+    }
+}