diff --git a/README.md b/README.md
index c7dfcc5..6ac8fe3 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,8 @@ specification for hosting profile images tied to email or OpenID addresses.
 * SHA256 hashes
 * Variable image size (`s` or `size`)
 * Default fallbacks (`d` or `default`): 404, mp/mm, identicon (=retro), retro
-* Requesting file type by appending `.jpg`, `.png` or `.gif` to the hash
+* Requesting file type by appending `.jpg`, `.png`, `.gif` or `.webp` to the
+  hash
 
 The API is explained in greater detail at the
 [Libravar wiki](https://wiki.libravatar.org/api/).
@@ -49,7 +50,9 @@ _avatars-sec._tcp.example.com. IN SRV 0 0 443 avatars.example.com
 HTTPS.
 
 libravatarserv looks in the current working directory for images. You can force
-a different directory by setting the environment variable `LIBRAVATARSERV_DIR`.
+a different directory by setting the environment variable
+`LIBRAVATARSERV_DIR`. Any file format supported by ImageMagick is supported, but
+it should be PNG, JPEG or GIF for compatibility.
 
 The image files are named like your email address, no file extension. The
 default behaviour for unknown users is to return a 404 error. You can change