diff --git a/README.md b/README.md
index 36946a1..0607aec 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ imagesize = "0.12"
 * JPEG XL
 * KTX2
 * PNG
+* PNM (PBM, PGM, PPM)
 * PSD / PSB
 * QOI
 * TGA