diff --git a/web/src/app.css b/web/src/app.css
index 243c323..725b3ea 100644
--- a/web/src/app.css
+++ b/web/src/app.css
@@ -82,3 +82,42 @@ select {
 	outline-offset: 2px;
 	border-radius: var(--radius-s);
 }
+
+button.primary,
+button.secondary {
+	padding: var(--space-2) var(--space-3);
+	border-radius: var(--radius-s);
+	border: 1px solid transparent;
+	font-weight: 600;
+	font-size: 0.95rem;
+	cursor: pointer;
+	transition:
+		background 120ms ease,
+		border-color 120ms ease,
+		color 120ms ease;
+}
+
+button.primary {
+	background: var(--accent);
+	color: #ffffff;
+}
+
+button.primary:hover:not(:disabled) {
+	background: var(--accent-hover);
+}
+
+button.secondary {
+	background: var(--surface);
+	color: var(--text);
+	border-color: var(--border);
+}
+
+button.secondary:hover:not(:disabled) {
+	border-color: var(--accent);
+	color: var(--accent);
+}
+
+button:disabled {
+	opacity: 0.55;
+	cursor: not-allowed;
+}
diff --git a/web/src/lib/components/DownloadButton.svelte b/web/src/lib/components/DownloadButton.svelte
new file mode 100644
index 0000000..1658f01
--- /dev/null
+++ b/web/src/lib/components/DownloadButton.svelte
@@ -0,0 +1,41 @@
+<script lang="ts">
+	import { downloadBlob, encode } from '$lib/core/io';
+	import type { PixelImage } from '$lib/core/types';
+	import type { OutputFormat } from '$lib/registry';
+
+	let {
+		image,
+		format,
+		baseName,
+		params,
+		onError
+	}: {
+		image: PixelImage | null;
+		format?: OutputFormat;
+		baseName: string;
+		params: Record<string, unknown>;
+		onError?: (e: unknown) => void;
+	} = $props();
+
+	let busy = $state(false);
+
+	async function download() {
+		if (!image || !format || busy) return;
+		busy = true;
+		try {
+			const raw = format.qualityParamId ? params[format.qualityParamId] : undefined;
+			const quality =
+				typeof raw === 'number' ? Math.min(Math.max(raw, 1), 100) / 100 : undefined;
+			const blob = await encode(image, format.mime, quality);
+			downloadBlob(blob, `${baseName}.${format.ext}`);
+		} catch (e) {
+			onError?.(e);
+		} finally {
+			busy = false;
+		}
+	}
+</script>
+
+<button class="primary" onclick={download} disabled={!image || !format || busy}>
+	{busy ? 'Готовим файл…' : `Скачать .${format?.ext ?? 'png'}`}
+</button>
diff --git a/web/src/lib/components/DropZone.svelte b/web/src/lib/components/DropZone.svelte
new file mode 100644
index 0000000..c9a697e
--- /dev/null
+++ b/web/src/lib/components/DropZone.svelte
@@ -0,0 +1,107 @@
+<script lang="ts">
+	import { ACCEPTED_IMAGE_TYPES } from '$lib/core/io';
+
+	let {
+		onFile,
+		onError,
+		label = 'Перетащите изображение сюда или нажмите, чтобы выбрать файл'
+	}: {
+		onFile: (file: File) => void;
+		onError?: (message: string) => void;
+		label?: string;
+	} = $props();
+
+	let input = $state<HTMLInputElement | undefined>();
+	let dragging = $state(false);
+
+	const acceptedMimes = new Set(ACCEPTED_IMAGE_TYPES.split(','));
+
+	function accept(file: File | undefined | null) {
+		if (!file) return;
+		if (!acceptedMimes.has(file.type)) {
+			onError?.(
+				`Неподдерживаемый формат файла (${file.type || 'неизвестный'}). Поддерживаются PNG, JPEG, WebP, GIF и BMP.`
+			);
+			return;
+		}
+		onFile(file);
+	}
+
+	function openPicker() {
+		input?.click();
+	}
+</script>
+
+<div
+	class="dropzone"
+	class:dragging
+	role="button"
+	tabindex="0"
+	aria-label={label}
+	onclick={openPicker}
+	onkeydown={(e) => {
+		if (e.key === 'Enter' || e.key === ' ') {
+			e.preventDefault();
+			openPicker();
+		}
+	}}
+	ondragover={(e) => {
+		e.preventDefault();
+		dragging = true;
+	}}
+	ondragleave={() => (dragging = false)}
+	ondrop={(e) => {
+		e.preventDefault();
+		dragging = false;
+		accept(e.dataTransfer?.files[0]);
+	}}
+>
+	<span aria-hidden="true" class="icon">⬇</span>
+	{label}
+</div>
+<input
+	bind:this={input}
+	type="file"
+	accept={ACCEPTED_IMAGE_TYPES}
+	hidden
+	onchange={() => {
+		accept(input?.files?.[0]);
+		if (input) {
+			input.value = '';
+		}
+	}}
+/>
+
+<style>
+	.dropzone {
+		display: flex;
+		flex-direction: column;
+		align-items: center;
+		justify-content: center;
+		gap: var(--space-2);
+		min-height: 14rem;
+		padding: var(--space-4);
+		border: 2px dashed var(--border);
+		border-radius: var(--radius-m);
+		background: var(--surface);
+		color: var(--text-muted);
+		text-align: center;
+		cursor: pointer;
+		user-select: none;
+		transition:
+			border-color 120ms ease,
+			background 120ms ease;
+	}
+
+	.dropzone:hover,
+	.dropzone:focus-visible,
+	.dragging {
+		border-color: var(--accent);
+		background: color-mix(in srgb, var(--accent) 6%, var(--surface));
+	}
+
+	.icon {
+		font-size: 1.8rem;
+		line-height: 1;
+	}
+</style>
diff --git a/web/src/lib/components/InfoPanel.svelte b/web/src/lib/components/InfoPanel.svelte
new file mode 100644
index 0000000..88b863f
--- /dev/null
+++ b/web/src/lib/components/InfoPanel.svelte
@@ -0,0 +1,49 @@
+<script lang="ts">
+	import type { ImageInfo } from '$lib/core/analyze';
+
+	let { info }: { info: ImageInfo | null } = $props();
+</script>
+
+{#if info}
+	<dl>
+		<div>
+			<dt>Размеры</dt>
+			<dd>{info.width} × {info.height} px</dd>
+		</div>
+		<div>
+			<dt>Альфа-канал</dt>
+			<dd>{info.hasAlpha ? 'есть — есть полупрозрачные пиксели' : 'нет'}</dd>
+		</div>
+		<div>
+			<dt>Уникальных цветов (RGBA)</dt>
+			<dd>{info.colorCount.toLocaleString('ru-RU')}</dd>
+		</div>
+	</dl>
+{/if}
+
+<style>
+	dl {
+		display: grid;
+		gap: var(--space-2);
+		margin: var(--space-3) 0;
+	}
+
+	dl > div {
+		display: flex;
+		justify-content: space-between;
+		gap: var(--space-3);
+		padding: var(--space-2) var(--space-3);
+		background: var(--surface);
+		border: 1px solid var(--border);
+		border-radius: var(--radius-s);
+	}
+
+	dt {
+		color: var(--text-muted);
+	}
+
+	dd {
+		margin: 0;
+		font-family: var(--font-mono);
+	}
+</style>
diff --git a/web/src/lib/components/ParamForm.svelte b/web/src/lib/components/ParamForm.svelte
new file mode 100644
index 0000000..b821aa6
--- /dev/null
+++ b/web/src/lib/components/ParamForm.svelte
@@ -0,0 +1,89 @@
+<script lang="ts">
+	import type { ParamDef } from '$lib/registry';
+
+	let {
+		params,
+		values = $bindable()
+	}: {
+		params: ParamDef[];
+		values: Record<string, any>;
+	} = $props();
+</script>
+
+{#each params as param (param.id)}
+	<div class="field">
+		{#if param.type === 'checkbox'}
+			<label class="checkbox">
+				<input type="checkbox" bind:checked={values[param.id]} />
+				{param.label}
+			</label>
+		{:else}
+			<label for={param.id}>{param.label}</label>
+			{#if param.type === 'number'}
+				<input
+					id={param.id}
+					type="number"
+					min={param.min}
+					max={param.max}
+					step={param.step}
+					bind:value={values[param.id]}
+				/>
+			{:else if param.type === 'select'}
+				<select id={param.id} bind:value={values[param.id]}>
+					{#each param.options as option (option.value)}
+						<option value={option.value}>{option.label}</option>
+					{/each}
+				</select>
+			{:else if param.type === 'color'}
+				<input id={param.id} type="color" bind:value={values[param.id]} />
+			{/if}
+		{/if}
+	</div>
+{/each}
+
+<style>
+	.field {
+		display: flex;
+		flex-direction: column;
+		gap: var(--space-1);
+		margin-bottom: var(--space-3);
+	}
+
+	label,
+	.checkbox {
+		font-size: 0.9rem;
+		color: var(--text-muted);
+	}
+
+	input,
+	select {
+		padding: var(--space-1) var(--space-2);
+		border: 1px solid var(--border);
+		border-radius: var(--radius-s);
+		background: var(--surface);
+		max-width: 16rem;
+	}
+
+	input[type='number'] {
+		font-family: var(--font-mono);
+	}
+
+	input[type='color'] {
+		height: 2.4rem;
+		padding: 2px;
+		cursor: pointer;
+	}
+
+	.checkbox {
+		display: flex;
+		align-items: center;
+		gap: var(--space-2);
+		color: var(--text);
+		cursor: pointer;
+	}
+
+	.checkbox input {
+		width: 1rem;
+		height: 1rem;
+	}
+</style>
diff --git a/web/src/lib/components/Preview.svelte b/web/src/lib/components/Preview.svelte
new file mode 100644
index 0000000..1a1090b
--- /dev/null
+++ b/web/src/lib/components/Preview.svelte
@@ -0,0 +1,40 @@
+<script lang="ts">
+	import type { PixelImage } from '$lib/core/types';
+
+	let { image }: { image: PixelImage | null } = $props();
+
+	let canvas = $state<HTMLCanvasElement | undefined>();
+
+	$effect(() => {
+		if (!canvas || !image) return;
+		canvas.width = image.width;
+		canvas.height = image.height;
+		const ctx = canvas.getContext('2d');
+		if (!ctx) return;
+		ctx.putImageData(new ImageData(image.data, image.width, image.height), 0, 0);
+	});
+</script>
+
+{#if image}
+	<canvas bind:this={canvas} title="{image.width} × {image.height}"></canvas>
+	<p class="dims">{image.width} × {image.height} px</p>
+{/if}
+
+<style>
+	canvas {
+		display: block;
+		max-width: 100%;
+		max-height: 24rem;
+		background:
+			repeating-conic-gradient(var(--check-a) 0% 25%, var(--check-b) 0% 50%);
+		background-size: 16px 16px;
+		border: 1px solid var(--border);
+		border-radius: var(--radius-m);
+	}
+
+	.dims {
+		margin-top: var(--space-1);
+		color: var(--text-muted);
+		font-size: 0.85rem;
+	}
+</style>
diff --git a/web/src/lib/components/ToolPage.svelte b/web/src/lib/components/ToolPage.svelte
new file mode 100644
index 0000000..f24e2e3
--- /dev/null
+++ b/web/src/lib/components/ToolPage.svelte
@@ -0,0 +1,187 @@
+<script lang="ts">
+	import { imageInfo, type ImageInfo } from '$lib/core/analyze';
+	import { decodeFile } from '$lib/core/io';
+	import type { PixelImage } from '$lib/core/types';
+	import { defaultParams, outputOf, type ToolEntry } from '$lib/registry';
+	import DownloadButton from './DownloadButton.svelte';
+	import DropZone from './DropZone.svelte';
+	import InfoPanel from './InfoPanel.svelte';
+	import ParamForm from './ParamForm.svelte';
+	import Preview from './Preview.svelte';
+
+	let { tool }: { tool: ToolEntry } = $props();
+
+	type Status = 'idle' | 'loaded' | 'processing' | 'error';
+
+	let status = $state<Status>('idle');
+	let source = $state<PixelImage | null>(null);
+	let result = $state<PixelImage | null>(null);
+	let info = $state<ImageInfo | null>(null);
+	let errorText = $state('');
+	let values = $state<Record<string, any>>({});
+
+	const isInfo = $derived(tool.resultType === 'info');
+
+	async function handleFile(file: File) {
+		errorText = '';
+		status = 'processing';
+		try {
+			source = await decodeFile(file);
+			values = defaultParams(tool);
+			result = null;
+			info = isInfo ? imageInfo(source) : null;
+			if (isInfo) {
+				status = 'loaded';
+			} else {
+				await apply();
+			}
+		} catch (e) {
+			showError(e);
+		}
+	}
+
+	async function apply() {
+		if (!source || isInfo || status === 'processing') return;
+		errorText = '';
+		status = 'processing';
+		try {
+			result = await tool.run(source, values);
+			status = 'loaded';
+		} catch (e) {
+			showError(e);
+		}
+	}
+
+	function showError(e: unknown) {
+		status = source ? 'loaded' : 'idle';
+		errorText = e instanceof Error ? e.message : String(e);
+	}
+
+	function reset() {
+		source = null;
+		result = null;
+		info = null;
+		errorText = '';
+		status = 'idle';
+		values = defaultParams(tool);
+	}
+</script>
+
+<section>
+	<h1>{tool.title}</h1>
+	<p class="description">{tool.description}</p>
+
+	{#if errorText}
+		<div class="error" role="alert">{errorText}</div>
+	{/if}
+
+	{#if !source}
+		<DropZone onFile={handleFile} onError={(message) => (errorText = message)} />
+	{:else}
+		<div class="layout">
+			<div class="result-col">
+				<h2>{isInfo ? 'Изображение' : 'Результат'}</h2>
+				{#if status === 'processing' && !result}
+					<p class="hint">Обработка…</p>
+				{:else}
+					<Preview image={isInfo ? source : result} />
+				{/if}
+				{#if isInfo && info}
+					<InfoPanel {info} />
+				{/if}
+				<button class="secondary" onclick={reset}>Загрузить другое изображение</button>
+			</div>
+
+			{#if !isInfo}
+				<div class="params-col">
+					<h2>Параметры</h2>
+					{#if tool.params.length > 0}
+						<ParamForm params={tool.params} bind:values />
+						<button class="primary" onclick={apply} disabled={status === 'processing'}>
+							{status === 'processing' ? 'Обработка…' : 'Применить'}
+						</button>
+					{:else}
+						<p class="hint">У этого инструмента нет параметров — результат уже готов.</p>
+					{/if}
+					<div class="download-row">
+						<DownloadButton
+							image={result}
+							format={outputOf(tool)}
+							baseName={tool.id}
+							params={values}
+							onError={showError}
+						/>
+					</div>
+				</div>
+			{/if}
+		</div>
+	{/if}
+</section>
+
+<style>
+	h1 {
+		margin-bottom: var(--space-1);
+	}
+
+	.description {
+		color: var(--text-muted);
+		max-width: 48rem;
+		margin-bottom: var(--space-4);
+	}
+
+	.error {
+		padding: var(--space-2) var(--space-3);
+		margin-bottom: var(--space-3);
+		border: 1px solid #e5484d;
+		border-radius: var(--radius-s);
+		background: color-mix(in srgb, #e5484d 8%, var(--surface));
+		color: #b3261e;
+		font-size: 0.9rem;
+	}
+
+	.layout {
+		display: grid;
+		grid-template-columns: minmax(0, 1fr) minmax(16rem, 20rem);
+		gap: var(--space-5);
+		align-items: start;
+	}
+
+	@media (max-width: 48rem) {
+		.layout {
+			grid-template-columns: 1fr;
+		}
+	}
+
+	.result-col h2,
+	.params-col h2 {
+		margin-bottom: var(--space-2);
+		font-size: 1rem;
+		color: var(--text-muted);
+		text-transform: uppercase;
+		letter-spacing: 0.04em;
+	}
+
+	.result-col button.secondary {
+		margin-top: var(--space-3);
+	}
+
+	.params-col button.primary {
+		width: 100%;
+	}
+
+	.download-row {
+		margin-top: var(--space-4);
+		padding-top: var(--space-3);
+		border-top: 1px solid var(--border);
+	}
+
+	.download-row :global(button) {
+		width: 100%;
+	}
+
+	.hint {
+		color: var(--text-muted);
+		font-size: 0.9rem;
+		margin-bottom: var(--space-3);
+	}
+</style>