seed can be specified to reproduce output

config.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"time"
 )
 
 type Config struct {
@@ -21,6 +22,7 @@ type Config struct {
 	Sepia        bool
 	Amount       int
 	Quiet        bool
+	Seed         int64
 }
 
 // loads configuration values from json file
@@ -47,6 +49,9 @@ func (c *Config) SetOutputDimensions() {
 }
 
 func initConfigRegister() {
+	// default seed for the RNG
+	seed := time.Now().UnixNano()
+
 	// command line arguments
 	flag.StringVar(&ConfigRegister.Method, "blending", "darken", "Blending methods : darken, lighten, average, fuckyfun")
 	flag.StringVar(&ConfigRegister.OutputDir, "output", "./", "Output directory")
@@ -56,7 +61,9 @@ func initConfigRegister() {
 	flag.BoolVar(&ConfigRegister.Grayscale, "grayscale", false, "Output image in shade of gray (around 50)")
 	flag.BoolVar(&ConfigRegister.Sepia, "sepia", false, "Output image with sepia tone")
 	flag.IntVar(&ConfigRegister.Amount, "amount", 2, "Number of images to blend together")
+	flag.Int64Var(&ConfigRegister.Seed, "seed", seed, "Number of images to blend together")
 	flag.BoolVar(&ConfigRegister.Quiet, "quiet", false, "No progress messages")
+
 	flag.Parse()
 
 	// set output's width and height

fs.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"time"
 )
 
 // load an image from a file into an Image value
@@ -52,7 +51,6 @@ func getImagesList(path string) []string {
 
 // Randomly choose x number of image from a given folder
 func getRandomImage() string {
-	rand.Seed(time.Now().UnixNano())
 	dir := getImagesList(ConfigRegister.InputDir)
 	index := rand.Intn(len(dir))
 	return dir[index]

main.go

@@ -5,6 +5,7 @@ import (
 	_ "image/png"
 	"io/ioutil"
 	"log"
+	"math/rand"
 )
 
 func main() {
@@ -16,6 +17,10 @@ func main() {
 
 	}
 
+	// init RNG
+	rand.Seed(ConfigRegister.Seed)
+	log.Println("Seed :", ConfigRegister.Seed)
+
 	// pool of workers unionizing, ready to blend a new picture using the power of friendship
 	var pool blendWorkerPool