diff --git a/ext/image/main.php b/ext/image/main.php
index e0c30ce3..a888f357 100644
--- a/ext/image/main.php
+++ b/ext/image/main.php
@@ -167,6 +167,16 @@ class ImageIO extends Extension {
 		global $database;
 		global $config;
 
+		/*
+		 * Validate things
+		 */
+		if(!empty($image->source)) {
+			if(!preg_match("#^(https?|ftp)://#", $image->source)) {
+				$error = "Image's source isn't a valid URL";
+				return $error;
+			}
+		}
+
 		/*
 		 * Check for an existing image
 		 */