diff --git a/README.md b/README.md
index 5c2e0a9..4c3496d 100644
--- a/README.md
+++ b/README.md
@@ -68,7 +68,7 @@ shader_type canvas_item;
 
 #include "res://shaderlib/hsv.gdshaderinc"
 
-//!load ./swamp.jpg
+//!load ./examples/images/swamp.jpg
 
 void fragment() {
 	COLOR = hsv_offset(COLOR, 0.32, 0.2, 0.0);
diff --git a/examples/channel_offset.gdshader b/examples/channel_offset.gdshader
index 73915ea..a1ad8b5 100644
--- a/examples/channel_offset.gdshader
+++ b/examples/channel_offset.gdshader
@@ -1,6 +1,6 @@
 shader_type canvas_item;
 
-//!load ./swamp.jpg
+//!load ./images/swamp.jpg
 
 const vec2 offset_r = vec2(-0.002, -0.002);
 const vec2 offset_g = vec2(0., 0.);
diff --git a/examples/color_and_pixelate.gdshader b/examples/color_and_pixelate.gdshader
new file mode 100644
index 0000000..7c2c0ef
--- /dev/null
+++ b/examples/color_and_pixelate.gdshader
@@ -0,0 +1,13 @@
+shader_type canvas_item;
+
+#include "res://shaderlib/hsv.gdshaderinc"
+#include "res://shaderlib/effects.gdshaderinc"
+
+//!load ./images/swamp.jpg
+
+void fragment() {
+	COLOR = pixelate(TEXTURE, UV, 200.0);
+	vec4 hsv = rgb2hsv(COLOR);
+	COLOR = hsv_offset(COLOR, 0.65, .42-(hsv.y*.3), -.125);
+	COLOR = hsv_multiply(COLOR, 1.0, 1.0, 1.25);
+}
diff --git a/examples/denoise.gdshader b/examples/denoise.gdshader
new file mode 100644
index 0000000..09dabb6
--- /dev/null
+++ b/examples/denoise.gdshader
@@ -0,0 +1,9 @@
+shader_type canvas_item;
+
+//!load ./images/noisy.png
+
+#include "res://shaderlib/denoise.gdshaderinc"
+
+void fragment() {
+	COLOR = smart_denoise(TEXTURE, UV, 12.0, 1.0, .12);
+}
diff --git a/examples/greyscale.gdshader b/examples/greyscale.gdshader
index 921c591..00aac8b 100644
--- a/examples/greyscale.gdshader
+++ b/examples/greyscale.gdshader
@@ -1,6 +1,6 @@
 shader_type canvas_item;
 
-//!load ./swamp.jpg
+//!load ./images/swamp.jpg
 
 void fragment() {
 	float b = (COLOR.r + COLOR.g + COLOR.b) / 3.0;
diff --git a/examples/hsv.gdshader b/examples/hsv.gdshader
deleted file mode 100644
index b4d9100..0000000
--- a/examples/hsv.gdshader
+++ /dev/null
@@ -1,9 +0,0 @@
-shader_type canvas_item;
-
-#include "res://shaderlib/hsv.gdshaderinc"
-
-//!load ./swamp.jpg
-
-void fragment() {
-	COLOR = hsv_multiply(hsv_offset(COLOR, -0.3, 0.9, 0.0), 1.0, 0.44, 1.0);
-}
diff --git a/examples/CREDITS.md b/examples/images/CREDITS.md
similarity index 100%
rename from examples/CREDITS.md
rename to examples/images/CREDITS.md
diff --git a/examples/grass.png b/examples/images/grass.png
similarity index 100%
rename from examples/grass.png
rename to examples/images/grass.png
diff --git a/examples/grass.png.import b/examples/images/grass.png.import
similarity index 72%
rename from examples/grass.png.import
rename to examples/images/grass.png.import
index f9a52a6..327f716 100644
--- a/examples/grass.png.import
+++ b/examples/images/grass.png.import
@@ -3,15 +3,15 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://c1mh1d2f3u4ju"
-path="res://.godot/imported/grass.png-30af7213ed2d70b810b4ae788314a9e9.ctex"
+path="res://.godot/imported/grass.png-61a458998da568ce60ccb8a0c7caaf6d.ctex"
 metadata={
 "vram_texture": false
 }
 
 [deps]
 
-source_file="res://examples/grass.png"
-dest_files=["res://.godot/imported/grass.png-30af7213ed2d70b810b4ae788314a9e9.ctex"]
+source_file="res://examples/images/grass.png"
+dest_files=["res://.godot/imported/grass.png-61a458998da568ce60ccb8a0c7caaf6d.ctex"]
 
 [params]
 
diff --git a/examples/images/noisy.png b/examples/images/noisy.png
new file mode 100644
index 0000000..08e0664
Binary files /dev/null and b/examples/images/noisy.png differ
diff --git a/examples/images/noisy.png.import b/examples/images/noisy.png.import
new file mode 100644
index 0000000..e8bab73
--- /dev/null
+++ b/examples/images/noisy.png.import
@@ -0,0 +1,34 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://cfe2d0qes5x87"
+path="res://.godot/imported/noisy.png-1b2e79340785c6c0f50d5bad5ce97356.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://examples/images/noisy.png"
+dest_files=["res://.godot/imported/noisy.png-1b2e79340785c6c0f50d5bad5ce97356.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1
diff --git a/examples/swamp.jpg b/examples/images/swamp.jpg
similarity index 100%
rename from examples/swamp.jpg
rename to examples/images/swamp.jpg
diff --git a/examples/swamp.jpg.import b/examples/images/swamp.jpg.import
similarity index 72%
rename from examples/swamp.jpg.import
rename to examples/images/swamp.jpg.import
index 3cc2a0b..e0efe23 100644
--- a/examples/swamp.jpg.import
+++ b/examples/images/swamp.jpg.import
@@ -3,15 +3,15 @@
 importer="texture"
 type="CompressedTexture2D"
 uid="uid://ckjb0agn5btv7"
-path="res://.godot/imported/swamp.jpg-8e3eac7e7aacce65638e712310cdb35c.ctex"
+path="res://.godot/imported/swamp.jpg-1dfdcd52a5ef03d42a82a7f06acefa98.ctex"
 metadata={
 "vram_texture": false
 }
 
 [deps]
 
-source_file="res://examples/swamp.jpg"
-dest_files=["res://.godot/imported/swamp.jpg-8e3eac7e7aacce65638e712310cdb35c.ctex"]
+source_file="res://examples/images/swamp.jpg"
+dest_files=["res://.godot/imported/swamp.jpg-1dfdcd52a5ef03d42a82a7f06acefa98.ctex"]
 
 [params]
 
diff --git a/examples/lowpass.gdshader b/examples/lowpass.gdshader
index d2d82c5..a84c2a2 100644
--- a/examples/lowpass.gdshader
+++ b/examples/lowpass.gdshader
@@ -1,15 +1,13 @@
 shader_type canvas_item;
 
-//!load ./swamp.jpg
+//!load ./images/swamp.jpg
 
 // Settings
-const float threshold = 0.5;
+const float threshold = 0.6;
 //
 
 void fragment() {
 	vec4 tex = texture(TEXTURE , UV);
-	COLOR.r = min(tex.r, threshold);
-	COLOR.g = min(tex.g, threshold);
-	COLOR.b = min(tex.b, threshold);
+	COLOR.rgb = min(tex.rgb, vec3(threshold));
 	COLOR.a = tex.a;
 }
diff --git a/examples/multistep_distort.gdshader b/examples/multistep_distort.gdshader
index d4cc0ba..cea638f 100644
--- a/examples/multistep_distort.gdshader
+++ b/examples/multistep_distort.gdshader
@@ -1,7 +1,7 @@
 shader_type canvas_item;
 
 //!steps 9
-//!load ./swamp.jpg
+//!load ./images/swamp.jpg
 
 const float strength = 0.01;
 
diff --git a/examples/place_texture.gdshader b/examples/place_texture.gdshader
index 282ee69..183d080 100644
--- a/examples/place_texture.gdshader
+++ b/examples/place_texture.gdshader
@@ -3,8 +3,8 @@ shader_type canvas_item;
 #include "res://shaderlib/transform.gdshaderinc"
 #include "res://shaderlib/transparency.gdshaderinc"
 
-//!load ./swamp.jpg
-//!load+ img2 ./grass.png
+//!load ./images/swamp.jpg
+//!load+ img2 ./images/grass.png
 
 uniform sampler2D img2: repeat_disable, filter_nearest;
 
diff --git a/project.godot b/project.godot
index 85223c5..c244ec2 100644
--- a/project.godot
+++ b/project.godot
@@ -11,7 +11,7 @@ config_version=5
 [application]
 
 config/name="Fragmented"
-config/version="v6.1"
+config/version="v6.2"
 run/main_scene="res://scenes/main.tscn"
 config/features=PackedStringArray("4.3", "Mobile")
 run/low_processor_mode=true
diff --git a/scenes/ui_container.tscn b/scenes/ui_container.tscn
index bc8d37f..6be4c94 100644
--- a/scenes/ui_container.tscn
+++ b/scenes/ui_container.tscn
@@ -134,6 +134,7 @@ offset_bottom = 32.0
 text = "Save As"
 
 [node name="SaveImageButton" type="Button" parent="Editor"]
+unique_name_in_owner = true
 layout_mode = 1
 anchors_preset = 1
 anchor_left = 1.0
@@ -141,6 +142,7 @@ anchor_right = 1.0
 offset_left = -72.0
 offset_bottom = 32.0
 grow_horizontal = 0
+disabled = true
 text = "Export"
 
 [node name="FitImageButton" type="Button" parent="Editor"]
diff --git a/shaderlib/denoise.gdshaderinc b/shaderlib/denoise.gdshaderinc
new file mode 100644
index 0000000..322f6ec
--- /dev/null
+++ b/shaderlib/denoise.gdshaderinc
@@ -0,0 +1,66 @@
+
+/* glslSmartDenoise by Michele Morrone, adapted
+original code: https://github.com/BrutPitt/glslSmartDeNoise
+license of the original code:
+BSD 2-Clause License
+
+Copyright (c) 2019-2020 Michele Morrone
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#define INV_SQRT_OF_2PI 0.39894228040143267793994605993439  // 1.0/SQRT_OF_2PI
+#define INV_PI 0.31830988618379067153776752674503
+
+vec4 smart_denoise(sampler2D tex, vec2 uv, float sigma, float kSigma, float threshold) {
+	float radius = round(kSigma*sigma);
+	float radQ = radius * radius;
+
+	float invSigmaQx2 = .5 / (sigma * sigma);      // 1.0 / (sigma^2 * 2.0)
+	float invSigmaQx2PI = INV_PI * invSigmaQx2;    // 1/(2 * PI * sigma^2)
+
+	float invThresholdSqx2 = .5 / (threshold * threshold);     // 1.0 / (sigma^2 * 2.0)
+	float invThresholdSqrt2PI = INV_SQRT_OF_2PI / threshold;   // 1.0 / (sqrt(2*PI) * sigma^2)
+
+	vec4 centrPx = texture(tex,uv);
+
+	float zBuff = 0.0;
+	vec4 aBuff = vec4(0.0);
+	vec2 size = vec2(textureSize(tex, 0));
+
+	for (float dx = -radius; dx <= radius; dx++) {
+		float pt = sqrt(radQ - dx * dx);       // pt = yRadius: have circular trend
+		for (float dy = -pt; dy <= pt; dy++) {
+			vec2 d = vec2(dx, dy);
+			float blurFactor = exp( -dot(d, d) * invSigmaQx2 ) * invSigmaQx2PI;
+
+			vec4 walkPx =  texture(tex,uv+d/size);
+			vec4 dC = walkPx-centrPx;
+			float deltaFactor = exp(-dot(dC, dC) * invThresholdSqx2) * invThresholdSqrt2PI * blurFactor;
+
+			zBuff += deltaFactor;
+			aBuff += deltaFactor*walkPx;
+		}
+	}
+	return aBuff/zBuff;
+}
diff --git a/shaderlib/effects.gdshaderinc b/shaderlib/effects.gdshaderinc
new file mode 100644
index 0000000..d9b91f1
--- /dev/null
+++ b/shaderlib/effects.gdshaderinc
@@ -0,0 +1,14 @@
+
+// pixelate by lowering uv resolution
+vec4 pixelate(sampler2D tex, vec2 uv, float resolution_x) {
+	vec2 texture_size = vec2(textureSize(tex, 0));
+	vec2 ratio;
+	if (texture_size.x > texture_size.y) {
+		ratio = vec2(texture_size.x / texture_size.y, 1.0);
+	}
+	else {
+		ratio = vec2(1.0, texture_size.y / texture_size.x);
+	}
+	vec2 r = ratio * resolution_x;
+	return texture(tex, trunc(uv * r) / r);
+}
diff --git a/src/Compositor.gd b/src/Compositor.gd
index acc781a..0a8bf14 100644
--- a/src/Compositor.gd
+++ b/src/Compositor.gd
@@ -73,17 +73,17 @@ func update() -> Array: # returns error messages (strings)
 		mat.set_shader_parameter(
 			key, # uniform param name
 			Filesystem.additional_images[key])
+	# assign material
+	image_sprite.material = mat
 	# iterate n times
 	for i in range(steps):
 		# set STEP param
 		mat.set_shader_parameter("STEP", i)
-		# assign material
-		image_sprite.material = mat
 		# Get viewport texture
-		await RenderingServer.frame_post_draw # for good measure
+		await RenderingServer.frame_post_draw # wait for next frame to get drawn
 		Filesystem.result = get_texture().get_image()
-		image_sprite.material = null
 		image_sprite.texture = ImageTexture.create_from_image(Filesystem.result)
+	image_sprite.material = null
 	if fit_image:
 		camera.fit_image()
 	camera.update_vd_zoomlevel()
diff --git a/src/Editor.gd b/src/Editor.gd
index 69f9aab..edc4633 100644
--- a/src/Editor.gd
+++ b/src/Editor.gd
@@ -6,6 +6,8 @@ extends Control
 @onready var save_shader_dialog = %SaveShaderDialog
 @onready var ui_control_filesave = %SaveImageDialog
 
+@onready var save_image_button = %SaveImageButton
+
 @onready var status_indicator = %StatusIndicator
 @onready var error_msg_dialog = %ErrorMessageDialog
 
@@ -121,16 +123,24 @@ const gdshader_builtins = [
 	"POINT_COORD",
 	"SPECULAR_SHININESS"
 ]
+const gdshader_preprocessor = [
+	"define", "undef", "include", "pragma",
+	"if", "elif", "ifdef", "ifndef", "else", "endif"
+]
 # shaderlib
 var shaderlib_regex = {
 	"hsv": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/hsv\.gdshaderinc\"'),
 	"transform": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/transform\.gdshaderinc\"'),
-	"transparency": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/transparency\.gdshaderinc\"')
+	"transparency": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/transparency\.gdshaderinc\"'),
+	"effects": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/effects\.gdshaderinc\"'),
+	"denoise": RegEx.create_from_string(r'\s*\#include\s+\"res\:\/\/shaderlib\/denoise\.gdshaderinc\"')
 }
 const shaderlib_functions = {
 	"hsv": ["rgb2hsv", "hsv2rgb", "hsv_offset", "hsv_multiply"],
 	"transform": ["place_texture"],
 	"transparency": ["alpha_blend"],
+	"effects": ["pixelate"],
+	"denoise": ["smart_denoise"]
 }
 #
 # configure Highlighter
@@ -182,6 +192,9 @@ func _on_code_edit_code_completion_requested():
 	for k in gdshader_builtin_functions + gdshader_sub_functions:
 		code_editor.code_completion_prefixes.append(k)
 		code_editor.add_code_completion_option(CodeEdit.KIND_FUNCTION, k, k+"(", Color.INDIAN_RED)
+	for k in gdshader_preprocessor:
+		code_editor.code_completion_prefixes.append(k)
+		code_editor.add_code_completion_option(CodeEdit.KIND_PLAIN_TEXT, "#" + k, k)
 	# shaderlib #
 	var shader_code = code_editor.text
 	for key in shaderlib_regex:
@@ -257,12 +270,14 @@ func _on_fit_image_button_pressed():
 	camera.fit_image()
 
 func _on_apply_shader_button_pressed():
+	save_image_button.disabled = true
 	Filesystem.shader_code = code_editor.text
 	var errors = await compositor.update()
 	if len(errors) > 0:
 		update_status(Status.ERROR, "\n".join(errors))
 	else:
 		update_status(Status.OKAY)
+		save_image_button.disabled = false
 
 func _on_save_image_button_pressed():
 	if Filesystem.result != null:
diff --git a/src/Filesystem.gd b/src/Filesystem.gd
index 2ead478..0fb9507 100644
--- a/src/Filesystem.gd
+++ b/src/Filesystem.gd
@@ -61,15 +61,30 @@ func save_result(path: String):
 func load_shader(path: String):
 	print("Load ", path)
 	var file = FileAccess.open(path, FileAccess.READ)
-	self.shader_code = file.get_as_text()
-	if "/" in path: # update current working directory
-		self.cwd = path.substr(0, path.rfind("/"))
-	self.last_shader_savepath = path
+	if file != null:
+		self.shader_code = file.get_as_text()
+		if "/" in path: # update current working directory
+			self.cwd = path.substr(0, path.rfind("/"))
+		self.last_shader_savepath = path
+		store_last_opened_file()
 
 func save_shader(path: String):
 	print("Save ", path)
 	var file = FileAccess.open(path, FileAccess.WRITE)
 	file.store_string(self.shader_code)
+	file.flush()
 	if "/" in path: # update current working directory
 		self.cwd = path.substr(0, path.rfind("/"))
 	self.last_shader_savepath = path
+	store_last_opened_file()
+
+func store_last_opened_file():
+	var f = FileAccess.open("user://last_opened", FileAccess.WRITE)
+	if f != null:
+		f.store_pascal_string(last_shader_savepath)
+		f.flush()
+
+func remember_last_opened_file():
+	var f = FileAccess.open("user://last_opened", FileAccess.READ)
+	if f != null:
+		last_shader_savepath = f.get_pascal_string()
diff --git a/src/Main.gd b/src/Main.gd
index 6c59d07..2acdbf4 100644
--- a/src/Main.gd
+++ b/src/Main.gd
@@ -1,6 +1,7 @@
 extends Node
 
 @onready var editor_window = %EditorWindow
+@onready var ui_container = %UserInterfaceContainer
 @onready var app_name = ProjectSettings.get_setting("application/config/name")
 
 func _ready():
@@ -11,6 +12,10 @@ func _ready():
 		editor_window.position.y)
 	get_window().min_size = Vector2i(400, 400)
 	editor_window.min_size = Vector2i(560, 400)
+	# Load last opened file
+	Filesystem.remember_last_opened_file()
+	if Filesystem.last_shader_savepath != "":
+		ui_container.get_node("Editor")._on_open_shader_dialog_file_selected(Filesystem.last_shader_savepath)
 
 func update_title(current_file: String = ""):
 	if current_file == "":