now palette project lays here

util/stdio.go

@@ -1,8 +1,14 @@
-package imageutils
+package util
+
+import (
+	"image"
+	"image/png"
+	"os"
+)
 
 // ProcessImage takes input png image from stdin, processes it with f and outputs it to stdout.
-func ProcessStdio(f func(image.Image) image.Image) {
-      	img, err := png.Decode(os.Stdin)
+func ProcessStdio(f func(image.Image) image.Image) error {
+	img, err := png.Decode(os.Stdin)
 	if err != nil {
 		return err
 	}