Added support to 404 URLs in thumbnail generator

src/Helpers/TransferHelper.php

@@ -13,7 +13,14 @@ class TransferHelper
 		}
 
 		set_time_limit(0);
+		try
+		{
 			$srcHandle = fopen($srcUrl, 'rb');
+		}
+		catch (Exception $e)
+		{
+			throw new SimpleException('Cannot open URL for reading: ' . $e->getMessage());
+		}
 		if (!$srcHandle)
 			throw new SimpleException('Cannot open URL for reading');
 

src/ThumbnailGenerators/SmartThumbnailGenerator.php

@@ -5,10 +5,18 @@ class SmartThumbnailGenerator implements IThumbnailGenerator
 	{
 		$tmpPath = tempnam(sys_get_temp_dir(), 'thumb') . '.jpg';
 
+		try
+		{
 			TransferHelper::download(
 				$url,
 				$tmpPath,
 				null);
+		}
+		catch (SimpleException $e)
+		{
+			echo $e->getMessage();
+			return false;
+		}
 
 		$ret = self::generateFromFile($tmpPath, $dstPath, $width, $height);