diff --git a/src/dio/LICENSE.txt b/src/dio/LICENSE.txt
index a3236b421..11bc16b7b 100644
--- a/src/dio/LICENSE.txt
+++ b/src/dio/LICENSE.txt
@@ -1,4 +1,4 @@
-Copyright (c) 2018 Igara Studio S.A.
+Copyright (c) 2018-2021 Igara Studio S.A.
 Copyright (c) 2016-2018 David Capello
 
 Permission is hereby granted, free of charge, to any person obtaining
diff --git a/src/dio/decode_file.cpp b/src/dio/decode_file.cpp
index 234de9758..a440ba9e9 100644
--- a/src/dio/decode_file.cpp
+++ b/src/dio/decode_file.cpp
@@ -1,4 +1,5 @@
 // Aseprite Document IO Library
+// Copyright (c) 2021 Igara Studio S.A.
 // Copyright (c) 2017 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -22,8 +23,8 @@ bool decode_file(DecodeDelegate* delegate,
   assert(delegate);
   assert(f);
 
-  std::vector<uint8_t> buf(8, 0);
-  size_t n = f->readBytes(&buf[0], 8);
+  uint8_t buf[12];
+  size_t n = f->readBytes(&buf[0], 12);
   FileFormat format = detect_format_by_file_content_bytes(&buf[0], n);
   f->seek(0);                // Rewind
 
diff --git a/src/dio/detect_format.cpp b/src/dio/detect_format.cpp
index 65ed992ed..e0ed3155f 100644
--- a/src/dio/detect_format.cpp
+++ b/src/dio/detect_format.cpp
@@ -1,4 +1,5 @@
 // Aseprite Document IO Library
+// Copyright (c) 2021 Igara Studio S.A.
 // Copyright (c) 2016-2018 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -20,6 +21,8 @@
 #define GIF_89_STAMP     "GIF89a"
 #define PNG_MAGIC_DWORD1 0x474E5089
 #define PNG_MAGIC_DWORD2 0x0A1A0A0D
+#define WEBP_STAMP_1     "RIFF" // "RIFFnnnnWEBP"
+#define WEBP_STAMP_2     "WEBP"
 
 namespace dio {
 
@@ -47,6 +50,12 @@ FileFormat detect_format_by_file_content_bytes(const uint8_t* buf,
   if (n >= 2) {
     if (n >= 6) {
       if (n >= 8) {
+        if (n >= 12) {
+          if (std::strncmp((const char*)buf, WEBP_STAMP_1, 4) == 0 ||
+              std::strncmp((const char*)buf+8, WEBP_STAMP_2, 4) == 0)
+            return FileFormat::WEBP_ANIMATION;
+        }
+
         if (IS_MAGIC_DWORD(0, PNG_MAGIC_DWORD1) &&
             IS_MAGIC_DWORD(4, PNG_MAGIC_DWORD2))
           return FileFormat::PNG_IMAGE;
@@ -81,8 +90,8 @@ FileFormat detect_format_by_file_content(const std::string& filename)
     return FileFormat::ERROR;
 
   FILE* f = handle.get();
-  uint8_t buf[8];
-  int n = (int)fread(buf, 1, 8, f);
+  uint8_t buf[12];
+  int n = (int)fread(buf, 1, 12, f);
 
   return detect_format_by_file_content_bytes(buf, n);
 }
@@ -134,7 +143,7 @@ FileFormat detect_format_by_file_extension(const std::string& filename)
 
   if (ext == "png")
     return FileFormat::PNG_IMAGE;
-  
+
   if (ext == "svg")
     return FileFormat::SVG_IMAGE;