diff --git a/gallery_dl/extractor/nhentai.py b/gallery_dl/extractor/nhentai.py
index 09b2b167..90c5420f 100644
--- a/gallery_dl/extractor/nhentai.py
+++ b/gallery_dl/extractor/nhentai.py
@@ -61,7 +61,7 @@ class NhentaiGalleryExtractor(GalleryExtractor):
     def images(self, _):
         ufmt = ("https://i.nhentai.net/galleries/" +
                 self.data["media_id"] + "/{}.{}")
-        extdict = {"j": "jpg", "p": "png", "g": "gif"}
+        extdict = {"j": "jpg", "p": "png", "g": "gif", "w": "webp"}
 
         return [
             (ufmt.format(num, extdict.get(img["t"], "jpg")), {
diff --git a/test/results/nhentai.py b/test/results/nhentai.py
index 946acb3a..02667ac4 100644
--- a/test/results/nhentai.py
+++ b/test/results/nhentai.py
@@ -34,6 +34,19 @@ __tests__ = (
     "height"    : int,
 },
 
+{
+    "#url"     : "https://nhentai.net/g/538045/",
+    "#comment" : "webp (#6442)",
+    "#class"   : nhentai.NhentaiGalleryExtractor,
+    "#range"   : "4-7",
+    "#urls"    : (
+        "https://i.nhentai.net/galleries/3115523/4.jpg",
+        "https://i.nhentai.net/galleries/3115523/5.webp",
+        "https://i.nhentai.net/galleries/3115523/6.webp",
+        "https://i.nhentai.net/galleries/3115523/7.jpg",
+    ),
+},
+
 {
     "#url"     : "https://nhentai.net/tag/sole-female/",
     "#category": ("", "nhentai", "tag"),