diff --git a/packages/core/src/image/bmp.ts b/packages/core/src/image/bmp.ts
new file mode 100644
index 0000000..81ca274
--- /dev/null
+++ b/packages/core/src/image/bmp.ts
@@ -0,0 +1,24 @@
+export const BMP_HEADER_LENGTH = 54
+export function writeBMPHeader(buf: Buffer, iconSize: number, iconBytes: number, imagePPM: number): void {
+	// Uses header format BITMAPINFOHEADER https://en.wikipedia.org/wiki/BMP_file_format
+
+	// Bitmap file header
+	buf.write('BM')
+	buf.writeUInt32LE(iconBytes + 54, 2)
+	buf.writeInt16LE(0, 6)
+	buf.writeInt16LE(0, 8)
+	buf.writeUInt32LE(54, 10) // Full header size
+
+	// DIB header (BITMAPINFOHEADER)
+	buf.writeUInt32LE(40, 14) // DIB header size
+	buf.writeInt32LE(iconSize, 18)
+	buf.writeInt32LE(iconSize, 22)
+	buf.writeInt16LE(1, 26) // Color planes
+	buf.writeInt16LE(24, 28) // Bit depth
+	buf.writeInt32LE(0, 30) // Compression
+	buf.writeInt32LE(iconBytes, 34) // Image size
+	buf.writeInt32LE(imagePPM, 38) // Horizontal resolution ppm
+	buf.writeInt32LE(imagePPM, 42) // Vertical resolution ppm
+	buf.writeInt32LE(0, 46) // Colour pallette size
+	buf.writeInt32LE(0, 50) // 'Important' Colour count
+}
diff --git a/packages/core/src/image/index.ts b/packages/core/src/image/index.ts
new file mode 100644
index 0000000..6310229
--- /dev/null
+++ b/packages/core/src/image/index.ts
@@ -0,0 +1,26 @@
+import { jsImageToByteArray } from './nodejs'
+import { InternalFillImageOptions } from '../models/base'
+import { FillImageTargetOptions } from './options'
+
+export * from './bmp'
+export * from './options'
+
+// let wasmAppearsOk = true
+
+export function imageToByteArray(
+	imageBuffer: Buffer,
+	sourceOptions: InternalFillImageOptions,
+	targetOptions: FillImageTargetOptions,
+	destPadding: number,
+	imageSize: number
+): Buffer {
+	// try {
+	// 	if (wasmAppearsOk) {
+	// 		wasmImageToByteArray
+	// 	}
+	// } catch (e) {
+	// 	wasmAppearsOk = false
+	// }
+	return jsImageToByteArray(imageBuffer, sourceOptions, targetOptions, destPadding, imageSize)
+	//
+}
diff --git a/packages/core/src/util.ts b/packages/core/src/image/nodejs.ts
similarity index 57%
rename from packages/core/src/util.ts
rename to packages/core/src/image/nodejs.ts
index bfbc467..df4957d 100644
--- a/packages/core/src/util.ts
+++ b/packages/core/src/image/nodejs.ts
@@ -1,13 +1,7 @@
-import { InternalFillImageOptions } from './models/base'
+import { InternalFillImageOptions } from '../models/base'
+import { FillImageTargetOptions } from '../image/options'
 
-export interface FillImageTargetOptions {
-	colorMode: 'bgr' | 'rgba'
-	xFlip?: boolean
-	yFlip?: boolean
-	rotate?: boolean
-}
-
-export function imageToByteArray(
+export function jsImageToByteArray(
 	imageBuffer: Buffer,
 	sourceOptions: InternalFillImageOptions,
 	targetOptions: FillImageTargetOptions,
@@ -56,28 +50,3 @@ export function imageToByteArray(
 
 	return byteBuffer
 }
-
-export const BMP_HEADER_LENGTH = 54
-export function writeBMPHeader(buf: Buffer, iconSize: number, iconBytes: number, imagePPM: number): void {
-	// Uses header format BITMAPINFOHEADER https://en.wikipedia.org/wiki/BMP_file_format
-
-	// Bitmap file header
-	buf.write('BM')
-	buf.writeUInt32LE(iconBytes + 54, 2)
-	buf.writeInt16LE(0, 6)
-	buf.writeInt16LE(0, 8)
-	buf.writeUInt32LE(54, 10) // Full header size
-
-	// DIB header (BITMAPINFOHEADER)
-	buf.writeUInt32LE(40, 14) // DIB header size
-	buf.writeInt32LE(iconSize, 18)
-	buf.writeInt32LE(iconSize, 22)
-	buf.writeInt16LE(1, 26) // Color planes
-	buf.writeInt16LE(24, 28) // Bit depth
-	buf.writeInt32LE(0, 30) // Compression
-	buf.writeInt32LE(iconBytes, 34) // Image size
-	buf.writeInt32LE(imagePPM, 38) // Horizontal resolution ppm
-	buf.writeInt32LE(imagePPM, 42) // Vertical resolution ppm
-	buf.writeInt32LE(0, 46) // Colour pallette size
-	buf.writeInt32LE(0, 50) // 'Important' Colour count
-}
diff --git a/packages/core/src/image/options.ts b/packages/core/src/image/options.ts
new file mode 100644
index 0000000..46b205c
--- /dev/null
+++ b/packages/core/src/image/options.ts
@@ -0,0 +1,6 @@
+export interface FillImageTargetOptions {
+	colorMode: 'bgr' | 'rgba'
+	xFlip?: boolean
+	yFlip?: boolean
+	rotate?: boolean
+}
diff --git a/packages/core/src/image/wasm.ts b/packages/core/src/image/wasm.ts
new file mode 100644
index 0000000..949baf2
--- /dev/null
+++ b/packages/core/src/image/wasm.ts
@@ -0,0 +1,131 @@
+// Hack to get WebAssembly importable until https://github.com/microsoft/TypeScript-DOM-lib-generator/issues/826
+/// <reference lib="dom" />
+
+import * as path from 'path'
+import * as fs from 'fs'
+
+import { InternalFillImageOptions } from '../models/base'
+import { FillImageTargetOptions } from './options'
+
+const imports = {}
+let wasm: any = undefined
+
+let cachegetUint8Memory0: Uint8Array | null = null
+function getUint8Memory0() {
+	if (cachegetUint8Memory0 === null || cachegetUint8Memory0.buffer !== wasm.memory.buffer) {
+		cachegetUint8Memory0 = new Uint8Array(wasm.memory.buffer)
+	}
+	return cachegetUint8Memory0
+}
+
+export function wasmImageToByteArray(
+	imageBuffer: Uint8Array,
+	sourceOptions: InternalFillImageOptions,
+	targetOptions: FillImageTargetOptions,
+	destPadding: number,
+	imageSize: number
+): Uint8Array {
+	/**
+	 * This is based on what is given by wasm-pack, but has been adapted for better performance.
+	 * A lot of time was being spent on copying Buffers into wasm memory.
+	 *
+	 * We want to support taking subregions of the input Buffer/image. But with the default wrapping that would
+	 * result in copying in the full image every call. Or we could copy into a smaller buffer first, but that would
+	 * result in two copies. We can optimise away this excessive copying and keep it down at one copy.
+	 *
+	 * We know that the input value of dest is not interesting to wasm, so we can skip copying that
+	 *
+	 * Strings have been avoided, as they also incur an overhead
+	 */
+
+	const destLen = imageSize * imageSize * targetOptions.colorMode.length
+	const byteBuffer = Buffer.alloc(destPadding + destLen)
+
+	const srcFormatLen = sourceOptions.format.length
+	const srcLen = imageSize * imageSize * srcFormatLen
+
+	const flipColours = sourceOptions.format.substring(0, 3) !== targetOptions.colorMode.substring(0, 3)
+
+	let destPtr: any
+
+	try {
+		const srcPtr = wasm.__wbindgen_malloc(srcLen)
+
+		// Copy in the image subregion
+		const memory = getUint8Memory0()
+		const row_len = imageSize * srcFormatLen
+		if (sourceOptions.stride === row_len) {
+			// stride is a row, so we can take a shortcut
+			memory.set(imageBuffer.subarray(sourceOptions.offset, sourceOptions.offset + row_len * imageSize), 0)
+		} else {
+			// stride is more than a row, so we need to copy line by line
+			for (let y = 0; y < imageSize; y++) {
+				const row_start_src = y * sourceOptions.stride + sourceOptions.offset
+
+				memory.set(imageBuffer.subarray(row_start_src, row_start_src + row_len), y * row_len)
+			}
+		}
+
+		destPtr = wasm.__wbindgen_malloc(destLen)
+
+		wasmFunction(
+			srcPtr,
+			srcLen,
+			destPtr,
+			destLen,
+			srcFormatLen,
+			targetOptions.colorMode.length,
+			flipColours,
+			targetOptions.xFlip ?? false,
+			targetOptions.yFlip ?? false,
+			targetOptions.rotate ?? false,
+			imageSize
+		)
+
+		// Copy the result into the buffer
+		byteBuffer.set(getUint8Memory0().subarray(destPtr, destPtr + destLen), destPadding)
+	} finally {
+		// srcPtr is freed by the wasm binary
+
+		wasm.__wbindgen_free(destPtr, destLen)
+	}
+
+	return byteBuffer
+}
+
+function wasmFunction(
+	srcPtr: unknown,
+	srcLen: number,
+	destPtr: unknown,
+	destLen: number,
+	src_format_len: number,
+	dest_format_len: number,
+	flip_colours: boolean,
+	x_flip: boolean,
+	y_flip: boolean,
+	rotate: boolean,
+	image_size: number
+): void {
+	// Dange: the following call needs to match the rust implementation
+	wasm.image_to_byte_array(
+		srcPtr,
+		srcLen,
+		destPtr,
+		destLen,
+		src_format_len,
+		dest_format_len,
+		flip_colours,
+		x_flip,
+		y_flip,
+		rotate,
+		image_size
+	)
+}
+
+const wasmPath = path.join(__dirname, '../../../../wasm/pkg/streamdeck_wasm_bg.wasm')
+const wasmBytes = fs.readFileSync(wasmPath)
+
+const wasmModule = new WebAssembly.Module(wasmBytes)
+const wasmInstance = new WebAssembly.Instance(wasmModule, imports)
+wasm = wasmInstance.exports
+module.exports.__wasm = wasm
diff --git a/packages/core/src/models/base-gen2.ts b/packages/core/src/models/base-gen2.ts
index 2bbec2e..3c62722 100644
--- a/packages/core/src/models/base-gen2.ts
+++ b/packages/core/src/models/base-gen2.ts
@@ -1,5 +1,5 @@
 import { HIDDevice } from '../device'
-import { imageToByteArray } from '../util'
+import { imageToByteArray } from '../image'
 import {
 	EncodeJPEGHelper,
 	InternalFillImageOptions,
diff --git a/packages/core/src/models/mini.ts b/packages/core/src/models/mini.ts
index d9f69b7..aa7b81d 100644
--- a/packages/core/src/models/mini.ts
+++ b/packages/core/src/models/mini.ts
@@ -1,5 +1,5 @@
 import { HIDDevice } from '../device'
-import { BMP_HEADER_LENGTH, imageToByteArray, writeBMPHeader } from '../util'
+import { BMP_HEADER_LENGTH, imageToByteArray, writeBMPHeader } from '../image'
 import { InternalFillImageOptions, OpenStreamDeckOptions, StreamDeckProperties } from './base'
 import { StreamDeckGen1Base } from './base-gen1'
 import { DeviceModelId } from './id'
diff --git a/packages/core/src/models/original.ts b/packages/core/src/models/original.ts
index 3822481..b4a3cbc 100644
--- a/packages/core/src/models/original.ts
+++ b/packages/core/src/models/original.ts
@@ -1,5 +1,5 @@
 import { HIDDevice } from '../device'
-import { BMP_HEADER_LENGTH, imageToByteArray, writeBMPHeader } from '../util'
+import { BMP_HEADER_LENGTH, imageToByteArray, writeBMPHeader } from '../image'
 import { InternalFillImageOptions, OpenStreamDeckOptions, StreamDeckProperties } from './base'
 import { StreamDeckGen1Base } from './base-gen1'
 import { DeviceModelId, KeyIndex } from './id'
diff --git a/run.js b/run.js
new file mode 100644
index 0000000..8977369
--- /dev/null
+++ b/run.js
@@ -0,0 +1,57 @@
+/* eslint-disable node/no-unpublished-require */
+const { jsImageToByteArray } = require('./packages/core/dist/image/nodejs')
+// const wasm = require('./wasm/pkg/streamdeck_wasm')
+// const wasm = require('./wasm/wasm2')
+const { wasmImageToByteArray } = require('./packages/core/dist/image/wasm')
+
+const buf = Buffer.alloc(72 * 72 * 4)
+
+for (let aaa = 0; aaa < 10; aaa++) {
+	const count = 1000
+	let v
+	const start = Date.now()
+	for (let i = 0; i < count; i++) {
+		v = jsImageToByteArray(
+			buf,
+			{
+				format: 'rgba',
+				offset: 0,
+				stride: 72 * 3,
+			},
+			{
+				colorMode: 'bgr',
+				rotate: true,
+				xFlip: true,
+				yFlip: true,
+			},
+			0,
+			72
+		)
+	}
+	const done = Date.now()
+	console.log(`js took: ${done - start}ms over ${count} samples`)
+
+	const start2 = Date.now()
+	for (let i = 0; i < count; i++) {
+		// const b = Buffer.alloc(72 * 72 * 3)
+		// v = wasm.hello(buf, b, 'rgba', 72 * 3, 0, 'bgr', 0, true, true, true, 72)
+		v = wasmImageToByteArray(
+			buf,
+			{
+				format: 'rgba',
+				offset: 0,
+				stride: 72 * 3,
+			},
+			{
+				colorMode: 'bgr',
+				rotate: true,
+				xFlip: true,
+				yFlip: true,
+			},
+			0,
+			72
+		)
+	}
+	const done2 = Date.now()
+	console.log(`wasm took: ${done2 - start2}ms over ${count} samples`)
+}
diff --git a/wasm/.gitignore b/wasm/.gitignore
new file mode 100644
index 0000000..453b4c5
--- /dev/null
+++ b/wasm/.gitignore
@@ -0,0 +1,3 @@
+target
+pkg
+.idea
diff --git a/wasm/Cargo.lock b/wasm/Cargo.lock
new file mode 100644
index 0000000..c29b4ac
--- /dev/null
+++ b/wasm/Cargo.lock
@@ -0,0 +1,126 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "bumpalo"
+version = "3.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37ccbd214614c6783386c1af30caf03192f17891059cecc394b4fb119e363de3"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "streamdeck-wasm"
+version = "0.1.0"
+dependencies = [
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.96"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0748dd251e24453cb8717f0354206b91557e4ec8703673a4b30208f2abaf1ebf"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d22af068fba1eb5edcb4aea19d382b2a3deb4c8f9d475c589b6ada9e0fd493ee"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27370197c907c55e3f1a9fbe26f44e937fe6451368324e009cba39e139dc08ad"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53e04185bfa3a779273da532f5025e33398409573f348985af9a1cbf3774d3f4"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17cae7ff784d7e83a2fe7611cfe766ecf034111b49deb850a3dc7699c08251f5"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99ec0dc7a4756fffc231aab1b9f2f578d23cd391390ab27f952ae0c9b3ece20b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.80"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d554b7f530dee5964d9a9468d95c1f8b8acae4f282807e7d27d4b03099a46744"
diff --git a/wasm/Cargo.toml b/wasm/Cargo.toml
new file mode 100644
index 0000000..f09bbe7
--- /dev/null
+++ b/wasm/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "streamdeck-wasm"
+version = "0.1.0"
+edition = "2021"
+license = "MIT/Apache-2.0"
+
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+wasm-bindgen = "0.2"
diff --git a/wasm/src/lib.rs b/wasm/src/lib.rs
new file mode 100644
index 0000000..7585687
--- /dev/null
+++ b/wasm/src/lib.rs
@@ -0,0 +1,64 @@
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+pub fn image_to_byte_array(
+	src: &[u8],
+	dest: &mut [u8],
+	src_format_len: usize,
+	dest_format_len: usize,
+	flip_colours: bool,
+	x_flip: bool,
+	y_flip: bool,
+	rotate: bool,
+	image_size: usize,
+) {
+	// TODO - check buffer lengths?
+
+	let source_stride = image_size * src_format_len;
+	let dest_stride = image_size * dest_format_len;
+
+	for y in 0..image_size {
+		let row_offset = dest_stride * y;
+		for x in 0..image_size {
+			let (x2, y2) = {
+				let mut x2 = x;
+				let mut y2 = y;
+
+				if x_flip {
+					x2 = image_size - x2 - 1;
+				}
+				if y_flip {
+					y2 = image_size - y2 - 1;
+				}
+
+				if rotate {
+					(y2, x2)
+				} else {
+					(x2, y2)
+				}
+			};
+
+			let src_offset = y2 * source_stride + x2 * src_format_len;
+
+			let red = src[src_offset];
+			let green = src[src_offset + 1];
+			let blue = src[src_offset + 2];
+
+			let target_offset = row_offset + x * dest_format_len;
+			if flip_colours {
+				dest[target_offset] = blue;
+				dest[target_offset + 1] = green;
+				dest[target_offset + 2] = red;
+			} else {
+				dest[target_offset] = red;
+				dest[target_offset + 1] = green;
+				dest[target_offset + 2] = blue;
+			}
+
+			if dest_format_len > 3 {
+				dest[target_offset + 3] = 255;
+			}
+		}
+	}
+
+}