diff --git a/Makefile b/Makefile
index bc75bdf..f9d39c3 100644
--- a/Makefile
+++ b/Makefile
@@ -140,7 +140,7 @@ endef
 define resize
 echo "[resize]  "$@
 mkdir -p "$(dir $@)"
-convert -resize "$(1)x$(2)$(3)" $(4) "$^" "$@"
+convert -resize "$(1)x$(2)$(3)" -define webp:lossless=true $(4) "$^" "$@"
 endef
 
 # no args