diff --git a/src/lib/types.ts b/src/lib/types.ts
new file mode 100644
index 0000000..12ca8a0
--- /dev/null
+++ b/src/lib/types.ts
@@ -0,0 +1,216 @@
+// Core type definitions for 2eInk
+
+export type GreyLevel = 2 | 4 | 8 | 16 | 256;
+export type OutputFormat = 'png' | 'jpeg';
+export type ImageStatus = 'pending' | 'processing' | 'complete' | 'error';
+
+export interface Dimensions {
+	readonly width: number;
+	readonly height: number;
+}
+
+export interface Device {
+	readonly id: string;
+	readonly name: string;
+	readonly brand: string;
+	readonly width: number;
+	readonly height: number;
+	readonly greyLevels: GreyLevel;
+	readonly outputFormat: OutputFormat;
+}
+
+export interface ImageEntry {
+	readonly id: string;
+	readonly file: File;
+	readonly filename: string;
+	originalDimensions: Dimensions | null;
+	originalDataUrl: string | null;
+	processedBlob: Blob | null;
+	processedDataUrl: string | null;
+	status: ImageStatus;
+	error: string | null;
+	pipelineOverride: PipelineConfig | null;
+}
+
+export interface CustomDeviceFormData {
+	name: string;
+	width: number;
+	height: number;
+	greyLevels: GreyLevel;
+	outputFormat: OutputFormat;
+}
+
+export const CONSTRAINTS = {
+	MAX_FILE_SIZE_MB: 25,
+	MAX_FILE_SIZE_BYTES: 25 * 1024 * 1024,
+	MIN_DIMENSION: 100,
+	MAX_DIMENSION: 5000,
+	MAX_DEVICE_NAME_LENGTH: 50,
+	SUPPORTED_FORMATS: ['image/jpeg', 'image/png', 'image/webp'],
+	GREY_LEVEL_OPTIONS: [2, 4, 8, 16, 256],
+	OUTPUT_FORMAT_OPTIONS: ['png', 'jpeg']
+} as const;
+
+export function isSupportedFormat(file: File): boolean {
+	return CONSTRAINTS.SUPPORTED_FORMATS.includes(
+		file.type as (typeof CONSTRAINTS.SUPPORTED_FORMATS)[number]
+	);
+}
+
+export function getExtension(format: OutputFormat): string {
+	return format === 'jpeg' ? 'jpg' : 'png';
+}
+
+// Pipeline Configuration
+
+export type CropMode = 'center' | 'top' | 'bottom' | 'manual';
+export type ResizeMode = 'cover' | 'contain' | 'stretch';
+export type GreyscaleMethod = 'luminosity' | 'average' | 'lightness' | 'red' | 'green' | 'blue';
+export type DitherAlgorithm = 'floyd-steinberg' | 'ordered' | 'atkinson';
+
+export interface CropRegion {
+	x: number;
+	y: number;
+	width: number;
+	height: number;
+}
+
+export interface CropConfig {
+	enabled: boolean;
+	mode: CropMode;
+	region?: CropRegion;
+}
+
+export interface ResizeConfig {
+	enabled: boolean;
+	mode: ResizeMode;
+}
+
+export interface BrightnessConfig {
+	enabled: boolean;
+	value: number;
+}
+
+export interface ContrastConfig {
+	enabled: boolean;
+	value: number;
+}
+
+export interface GammaConfig {
+	enabled: boolean;
+	value: number;
+}
+
+export interface AutoLevelsConfig {
+	enabled: boolean;
+	clipPercent: number;
+}
+
+export interface GreyscaleConfig {
+	enabled: boolean;
+	method: GreyscaleMethod;
+}
+
+export interface SharpenConfig {
+	enabled: boolean;
+	amount: number;
+}
+
+export interface QuantizeConfig {
+	enabled: boolean;
+	levels: number;
+}
+
+export interface DitherConfig {
+	enabled: boolean;
+	algorithm: DitherAlgorithm;
+}
+
+export interface PipelineConfig {
+	crop: CropConfig;
+	resize: ResizeConfig;
+	brightness: BrightnessConfig;
+	contrast: ContrastConfig;
+	gamma: GammaConfig;
+	autoLevels: AutoLevelsConfig;
+	greyscale: GreyscaleConfig;
+	sharpen: SharpenConfig;
+	quantize: QuantizeConfig;
+	dither: DitherConfig;
+}
+
+export interface PipelinePreset {
+	id: string;
+	name: string;
+	config: PipelineConfig;
+	isBuiltIn: boolean;
+}
+
+export const DEFAULT_PIPELINE_CONFIG: PipelineConfig = {
+	crop: { enabled: true, mode: 'center' },
+	resize: { enabled: true, mode: 'cover' },
+	brightness: { enabled: false, value: 0 },
+	contrast: { enabled: true, value: 10 },
+	gamma: { enabled: false, value: 1.0 },
+	autoLevels: { enabled: false, clipPercent: 0.5 },
+	greyscale: { enabled: true, method: 'luminosity' },
+	sharpen: { enabled: false, amount: 0 },
+	quantize: { enabled: true, levels: 16 },
+	dither: { enabled: true, algorithm: 'floyd-steinberg' }
+};
+
+export const BUILT_IN_PRESETS: PipelinePreset[] = [
+	{
+		id: 'default',
+		name: 'Default',
+		config: DEFAULT_PIPELINE_CONFIG,
+		isBuiltIn: true
+	},
+	{
+		id: 'high-contrast',
+		name: 'High Contrast',
+		config: {
+			...DEFAULT_PIPELINE_CONFIG,
+			contrast: { enabled: true, value: 30 },
+			brightness: { enabled: true, value: 5 },
+			gamma: { enabled: true, value: 1.2 }
+		},
+		isBuiltIn: true
+	},
+	{
+		id: 'no-dither',
+		name: 'No Dither',
+		config: {
+			...DEFAULT_PIPELINE_CONFIG,
+			dither: { enabled: false, algorithm: 'floyd-steinberg' },
+			contrast: { enabled: false, value: 0 },
+			gamma: { enabled: false, value: 1.0 }
+		},
+		isBuiltIn: true
+	},
+	{
+		id: 'photo',
+		name: 'Photo (256 levels)',
+		config: {
+			...DEFAULT_PIPELINE_CONFIG,
+			quantize: { enabled: false, levels: 256 },
+			dither: { enabled: false, algorithm: 'floyd-steinberg' },
+			contrast: { enabled: true, value: 5 },
+			gamma: { enabled: true, value: 1.05 }
+		},
+		isBuiltIn: true
+	},
+	{
+		id: 'atkinson',
+		name: 'Atkinson Dither',
+		config: {
+			...DEFAULT_PIPELINE_CONFIG,
+			dither: { enabled: true, algorithm: 'atkinson' }
+		},
+		isBuiltIn: true
+	}
+];
+
+export function clonePipelineConfig(config: PipelineConfig): PipelineConfig {
+	return JSON.parse(JSON.stringify(config));
+}