diff --git a/libavcodec/pnm.c b/libavcodec/pnm.c
index 4843d14653..134e9f6065 100644
--- a/libavcodec/pnm.c
+++ b/libavcodec/pnm.c
@@ -138,7 +138,7 @@ int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s){
                 avctx->pix_fmt = PIX_FMT_GRAY16BE;
                 if (s->maxval != 65535)
                     avctx->pix_fmt = PIX_FMT_GRAY16;
-            } if (avctx->pix_fmt == PIX_FMT_RGB24) {
+            } else if (avctx->pix_fmt == PIX_FMT_RGB24) {
                 if (s->maxval > 255)
                     avctx->pix_fmt = PIX_FMT_RGB48BE;
             } else {