diff --git a/client/html/post_merge_side.tpl b/client/html/post_merge_side.tpl
index b2c1fc6..53dd31f 100644
--- a/client/html/post_merge_side.tpl
+++ b/client/html/post_merge_side.tpl
@@ -35,6 +35,7 @@
                     'image/gif': 'GIF',
                     'image/jpeg': 'JPEG',
                     'image/png': 'PNG',
+                    'image/webp': 'WEBP',
                     'video/webm': 'WEBM',
                     'video/mp4': 'MPEG-4',
                     'application/x-shockwave-flash': 'SWF',
diff --git a/client/html/post_readonly_sidebar.tpl b/client/html/post_readonly_sidebar.tpl
index c959655..48372f4 100644
--- a/client/html/post_readonly_sidebar.tpl
+++ b/client/html/post_readonly_sidebar.tpl
@@ -8,6 +8,7 @@
                     'image/gif': 'GIF',
                     'image/jpeg': 'JPEG',
                     'image/png': 'PNG',
+                    'image/webp': 'WEBP',
                     'video/webm': 'WEBM',
                     'video/mp4': 'MPEG-4',
                     'application/x-shockwave-flash': 'SWF',
diff --git a/client/js/views/post_upload_view.js b/client/js/views/post_upload_view.js
index b4d0c40..3ccf7f3 100644
--- a/client/js/views/post_upload_view.js
+++ b/client/js/views/post_upload_view.js
@@ -13,6 +13,7 @@ function _mimeTypeToPostType(mimeType) {
         'image/gif': 'image',
         'image/jpeg': 'image',
         'image/png': 'image',
+        'image/webp': 'image',
         'video/mp4': 'video',
         'video/webm': 'video',
     }[mimeType] || 'unknown';
@@ -113,6 +114,7 @@ class Url extends Uploadable {
             'jpg': 'image/jpeg',
             'png': 'image/png',
             'gif': 'image/gif',
+            'webp': 'image/webp',
             'mp4': 'video/mp4',
             'webm': 'video/webm',
         };
diff --git a/server/szurubooru/func/mime.py b/server/szurubooru/func/mime.py
index c83f744..8f069a1 100644
--- a/server/szurubooru/func/mime.py
+++ b/server/szurubooru/func/mime.py
@@ -18,6 +18,9 @@ def get_mime_type(content: bytes) -> str:
     if content[0:6] in (b'GIF87a', b'GIF89a'):
         return 'image/gif'
 
+    if content[8:12] == b'WEBP':
+        return 'image/webp'
+
     if content[0:4] == b'\x1A\x45\xDF\xA3':
         return 'video/webm'
 
@@ -33,6 +36,7 @@ def get_extension(mime_type: str) -> Optional[str]:
         'image/gif': 'gif',
         'image/jpeg': 'jpg',
         'image/png': 'png',
+        'image/webp': 'webp',
         'video/mp4': 'mp4',
         'video/webm': 'webm',
         'application/octet-stream': 'dat',
@@ -49,7 +53,7 @@ def is_video(mime_type: str) -> bool:
 
 
 def is_image(mime_type: str) -> bool:
-    return mime_type.lower() in ('image/jpeg', 'image/png', 'image/gif')
+    return mime_type.lower() in ('image/jpeg', 'image/png', 'image/gif', 'image/webp')
 
 
 def is_animated_gif(content: bytes) -> bool:
diff --git a/server/szurubooru/tests/assets/webp.webp b/server/szurubooru/tests/assets/webp.webp
new file mode 100644
index 0000000..d116e1e
Binary files /dev/null and b/server/szurubooru/tests/assets/webp.webp differ
diff --git a/server/szurubooru/tests/func/test_mime.py b/server/szurubooru/tests/func/test_mime.py
index 4b8dcfa..821ed20 100644
--- a/server/szurubooru/tests/func/test_mime.py
+++ b/server/szurubooru/tests/func/test_mime.py
@@ -9,6 +9,7 @@ from szurubooru.func import mime
     ('png.png', 'image/png'),
     ('jpeg.jpg', 'image/jpeg'),
     ('gif.gif', 'image/gif'),
+    ('webp.webp', 'image/webp'),
     ('text.txt', 'application/octet-stream'),
 ])
 def test_get_mime_type(read_asset, input_path, expected_mime_type):
@@ -26,6 +27,7 @@ def test_get_mime_type_for_empty_file():
     ('image/png', 'png'),
     ('image/jpeg', 'jpg'),
     ('image/gif', 'gif'),
+    ('image/webp', 'webp'),
     ('application/octet-stream', 'dat'),
 ])
 def test_get_extension(mime_type, expected_extension):