diff --git a/library/think/File.php b/library/think/File.php
index 21e8c9dd..bd39209f 100644
--- a/library/think/File.php
+++ b/library/think/File.php
@@ -195,12 +195,23 @@ class File extends SplFileObject
     {
         $extension = strtolower(pathinfo($this->getInfo('name'), PATHINFO_EXTENSION));
         /* 对图像文件进行严格检测 */
-        if (in_array($extension, ['gif', 'jpg', 'jpeg', 'bmp', 'png', 'swf']) && !in_array(exif_imagetype($this->filename), [1, 2, 3, 4, 6])) {
+        if (in_array($extension, ['gif', 'jpg', 'jpeg', 'bmp', 'png', 'swf']) && !in_array($this->getImageType($this->filename), [1, 2, 3, 4, 6])) {
             return false;
         }
         return true;
     }
 
+    // 判断图像类型
+    protected function getImageType($image)
+    {
+        if (function_exists('exif_imagetype')) {
+            return exif_imagetype($image);
+        } else {
+            $info = getimagesize($image);
+            return $info[2];
+        }
+    }
+
     /**
      * 检测上传文件大小
      * @param  integer   $size    最大大小
diff --git a/library/think/Validate.php b/library/think/Validate.php
index a88043a2..91707274 100644
--- a/library/think/Validate.php
+++ b/library/think/Validate.php
@@ -561,7 +561,7 @@ class Validate
                 $result = $value instanceof \think\File;
                 break;
             case 'image':
-                $result = $value instanceof \think\File && in_array(exif_imagetype($value->getRealPath()), [1, 2, 3, 6]);
+                $result = $value instanceof \think\File && in_array($this->getImageType($value->getRealPath()), [1, 2, 3, 6]);
                 break;
             default:
                 if (isset(self::$type[$rule])) {
@@ -575,6 +575,17 @@ class Validate
         return $result;
     }
 
+    // 判断图像类型
+    protected function getImageType($image)
+    {
+        if (function_exists('exif_imagetype')) {
+            return exif_imagetype($image);
+        } else {
+            $info = getimagesize($image);
+            return $info[2];
+        }
+    }
+
     /**
      * 验证是否为合格的域名或者IP 支持A，MX，NS，SOA，PTR，CNAME，AAAA，A6， SRV，NAPTR，TXT 或者 ANY类型
      * @access protected