diff --git a/config.json b/config.json
index b175a06..288059f 100644
--- a/config.json
+++ b/config.json
@@ -6,8 +6,9 @@
     "Width": 0,
     "Height": 0
   },
-  "Source": "tests/images/bash_test.png",
-  "Target": "atkinson.png",
+  "Source": "tests/images",
+  "Target": "temp",
+  "Include": [ ".png", ".jpg" ],
   "Exceptions": {
     "temp/painted_*.png": {
       "PixelWidth": 8,
diff --git a/data.go b/data.go
index 3e18b5b..336dfde 100644
--- a/data.go
+++ b/data.go
@@ -6,7 +6,6 @@ import (
   "log"
 )
 
-
 type Conversion struct {
   PixelWidth int
   ColorDepth int
@@ -18,6 +17,7 @@ type Conversion struct {
 type Settings struct {
   Source string
   Target string
+  Include []string
   Base Conversion
   Exceptions map[string]Conversion
 }
@@ -35,5 +35,9 @@ func LoadSettings(path string) Settings {
       log.Fatalf("json format error:", err)
   }
 
+  if len(settings.Include) == 0 {
+    log.Fatalf("You must have at least 1 extesion in Include in ", path)
+  }
+
   return settings
 }
diff --git a/filters/posterize.go b/filters/posterize.go
index 80276c7..48747fc 100644
--- a/filters/posterize.go
+++ b/filters/posterize.go
@@ -14,20 +14,23 @@ const (
   AtkinsonDither=2
 )
 
+const (
+  BIN_SIZE=math.MaxUint16+1
+)
 
 type PosterizeFilter struct {
   Depth uint16
-  Bins [math.MaxUint16]uint16
+  Bins [BIN_SIZE]uint16
   DitherType int
 }
 
 func Posterize(depth uint16, dither_type int) gift.Filter {
   var i uint16
-  var bins [math.MaxUint16]uint16
-  chunk := uint16((math.MaxUint16 + 1) / int(depth))
+  var bins [BIN_SIZE]uint16
+  chunk := uint16((BIN_SIZE) / int(depth))
 
   // BUG: this was fine with uint8, now it's dumb as hell
-  for i = 0; i < math.MaxUint16; i++ {
+  for i = 1; i < math.MaxUint16; i++ {
     bins[i] = (i / chunk) * chunk
   }
 
diff --git a/main.go b/main.go
index 6b1d3da..5d84f4b 100644
--- a/main.go
+++ b/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
   "flag"
+  "log"
 )
 
 type Opts struct {
@@ -21,6 +22,11 @@ func ParseOpts() Opts {
 
 func main() {
   opts := ParseOpts()
-  settings := LoadSettings(opts.Config)
-  JankImage(settings.Base, settings.Source, settings.Target)
+  config := LoadSettings(opts.Config)
+
+  err := RenderImages(config)
+
+  if err != nil {
+    log.Fatalf("failed to walk dir %s: %v", config.Source, err)
+  }
 }
diff --git a/processing.go b/processing.go
index 56f6c87..0cb976e 100644
--- a/processing.go
+++ b/processing.go
@@ -2,8 +2,13 @@ package main
 
 import (
   "os"
+  "io/fs"
+  "fmt"
+  "path/filepath"
+  "strings"
   "image"
   "log"
+  "regexp"
   "image/png"
   "github.com/disintegration/gift"
   "lcthw.dev/go/jankifier/filters"
@@ -48,3 +53,97 @@ func JankImage(settings Conversion, in_file string, out_file string) {
 
   SaveImage(out_file, out_img)
 }
+
+func UnfuckedPathSplit(path string) []string {
+	path = filepath.ToSlash(path)
+	// WARN: have to use strings.Split because fsnotify uses /, even on windows
+	return strings.Split(path, "/")[1:]
+}
+
+func SplitPathExt(path string) (string, string, bool) {
+	split_path := UnfuckedPathSplit(path)
+	source_name := strings.Join(split_path, "/") // Render wants / even on windows
+
+	ext := filepath.Ext(source_name)
+	source_name, found := strings.CutSuffix(source_name, ext)
+	return source_name, ext, found
+}
+
+func RePrefixPath(path string, new_prefix string) string {
+	split_path := UnfuckedPathSplit(path)
+
+	prefixed_path := append([]string{new_prefix}, split_path...)
+
+	res := filepath.Join(prefixed_path...)
+	return filepath.ToSlash(res)
+}
+
+func SamePath(a string, b string) bool {
+	return filepath.ToSlash(a) == filepath.ToSlash(b)
+}
+
+func MkdirPath(target_path string) error {
+	target_dir := filepath.Dir(target_path)
+	_, err := os.Stat(target_dir)
+
+	if os.IsNotExist(err) {
+		log.Println("MAKING: ", target_dir)
+		err = os.MkdirAll(target_dir, 0750)
+
+		if err != nil {
+          log.Fatal("making path to %s: %v", target_dir, err)
+		}
+	}
+
+	return nil
+}
+
+func Included(config Settings, path string) bool {
+  _, ext, found := SplitPathExt(path)
+  if !found { return false }
+
+  for _, include_ext := range config.Include {
+    if include_ext == ext {
+      return true
+    }
+  }
+
+  return false
+}
+
+func GetConversion(config Settings, path string) Conversion {
+  for key, conversion := range config.Exceptions {
+    match, err := regexp.MatchString(key, path)
+    if err != nil { log.Fatalf("problem matching regex %s: %v", key, err) }
+
+    if match {
+      return conversion
+    }
+  }
+
+  return config.Base
+}
+
+func RenderImages(config Settings) error {
+  err := filepath.WalkDir(config.Source,
+    func(path string, d fs.DirEntry, err error) error {
+    if !d.IsDir() && Included(config, path) {
+      target := RePrefixPath(path, config.Target)
+
+      err = MkdirPath(target)
+      if err != nil {
+        log.Fatalf("failed to make path %s: %v", path, err)
+      }
+
+      fmt.Println("FILE: ", path, "TARGET:", target)
+      convert := GetConversion(config, path)
+      JankImage(convert, path, target)
+    } else {
+      fmt.Println("SKIP:", path)
+    }
+
+    return nil
+  })
+
+  return err
+}