diff --git a/gallery_dl/extractor/nhentai.py b/gallery_dl/extractor/nhentai.py
index 90c5420f..0d656d04 100644
--- a/gallery_dl/extractor/nhentai.py
+++ b/gallery_dl/extractor/nhentai.py
@@ -11,6 +11,7 @@
 from .common import GalleryExtractor, Extractor, Message
 from .. import text, util
 import collections
+import random
 
 
 class NhentaiGalleryExtractor(GalleryExtractor):
@@ -59,15 +60,18 @@ class NhentaiGalleryExtractor(GalleryExtractor):
         }
 
     def images(self, _):
-        ufmt = ("https://i.nhentai.net/galleries/" +
-                self.data["media_id"] + "/{}.{}")
-        extdict = {"j": "jpg", "p": "png", "g": "gif", "w": "webp"}
+        exts = {"j": "jpg", "p": "png", "g": "gif", "w": "webp", "a": "avif"}
+
+        data = self.data
+        ufmt = ("https://i{}.nhentai.net/galleries/" +
+                data["media_id"] + "/{}.{}").format
 
         return [
-            (ufmt.format(num, extdict.get(img["t"], "jpg")), {
-                "width": img["w"], "height": img["h"],
+            (ufmt(random.randint(1, 4), num, exts.get(img["t"], "jpg")), {
+                "width" : img["w"],
+                "height": img["h"],
             })
-            for num, img in enumerate(self.data["images"]["pages"], 1)
+            for num, img in enumerate(data["images"]["pages"], 1)
         ]
 
 
diff --git a/test/results/nhentai.py b/test/results/nhentai.py
index 02667ac4..e10d8679 100644
--- a/test/results/nhentai.py
+++ b/test/results/nhentai.py
@@ -12,7 +12,8 @@ __tests__ = (
     "#url"     : "https://nhentai.net/g/147850/",
     "#category": ("", "nhentai", "gallery"),
     "#class"   : nhentai.NhentaiGalleryExtractor,
-    "#sha1_url": "5179dbf0f96af44005a0ff705a0ad64ac26547d0",
+    "#pattern" : r"https://i[1-4]\.nhentai\.net/galleries/867789/\d+\.jpg",
+    "#count"   : 16,
 
     "title"     : r"re:\[Morris\] Amazon no Hiyaku \| Amazon Elixir",
     "title_en"  : str,
@@ -39,11 +40,11 @@ __tests__ = (
     "#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",
+    "#pattern"    : (
+        r"https://i\d\.nhentai.net/galleries/3115523/4\.jpg",
+        r"https://i\d\.nhentai.net/galleries/3115523/5\.webp",
+        r"https://i\d\.nhentai.net/galleries/3115523/6\.webp",
+        r"https://i\d\.nhentai.net/galleries/3115523/7\.jpg",
     ),
 },