Image Optimization Tool

Optimize images without uploading them. Drop in a JPG, PNG or WebP and TryImager analyzes it locally, scores how well it is optimized for the web, explains what can be improved, and can optimize it automatically — all inside your browser.

Processed in your browserPrivate by design • No upload • No signup • No watermark

Drop an image here or browseJPG, PNG, WEBP, GIF, BMP, TIFF or SVG

Your image is processed locally in your browser. It is never uploaded to our servers. No fixed size limit — we adapt to what your device can handle. Very large files may take longer or show a warning.

Where will you use this image? (optional)

Displayed width in px (optional)

No display width given, so dimension recommendations are estimates based on a typical 1920 px layout.

What image optimization actually means

Image optimization is the process of shipping the smallest file that still looks right at the size it is displayed. Three things drive that number: the format you encode to, the pixel dimensions you ship, and how aggressively the encoder compresses. Getting all three roughly right usually matters far more than fine-tuning any single one.

Large images do not just cost bandwidth. Every byte has to arrive, decode and paint before a page feels finished, which is why oversized images are one of the most common causes of slow page loads on image-heavy sites. Optimized images can help reduce file size and improve web performance.

How the Image Optimization Score works

The score is deterministic — the same file always produces the same number — and every part of it is derived from properties measured in your browser.

File size (30%): total bytes a visitor must download. Around 150 KB or less is comfortable for a typical web image.
Format (20%): WebP and SVG score highest, JPEG scores well, PNG scores lower for photographic content without transparency, and legacy formats score lowest.
Dimensions (20%): your pixel width compared with the display width you enter, or an assumed width for the use case you pick. Roughly twice the display width covers high-density screens.
Compression (15%): bytes per pixel. Well-compressed web photos usually sit near 0.1–0.3 bytes per pixel.
Web readiness (15%): whether the format renders natively in browsers, plus penalties for very heavy payloads and very high megapixel counts.
Transparency (added when alpha is detected): whether the alpha channel is carried in an efficient format.

Formats: JPEG, PNG and WebP

JPEG is lossy and universally supported, which makes it a safe default for photographs — but it cannot store transparency and is usually larger than WebP at similar visual quality.

PNG is lossless. That is exactly what you want for logos, screenshots, and anything with a transparent background, and exactly what you do not want for photographs, where lossless encoding stores detail no one will ever see.

WebP covers both cases: lossy compression for photos and an alpha channel for transparency. Automatic optimization targets WebP, preserving transparency whenever it is detected.

Dimensions and transparency

A 4000 px wide photo displayed in an 800 px column downloads roughly five times the pixels it uses. Telling the optimizer the width you actually display makes its dimension recommendation exact rather than an estimate.

Transparency is detected by sampling the alpha channel of the decoded image, not by trusting the file extension. A PNG saved with a fully opaque background is treated as photographic content; a PNG with real transparency is optimized to WebP with the alpha channel preserved.

How automatic optimization works

Optimize Automatically picks an output format, a quality value and, when useful, smaller dimensions based on the analysis. It then encodes with the browser's native WebP encoder, validates that the result is genuinely a non-empty WebP file, and silently falls back to a libwebp WebAssembly encoder if the native path is missing or produces something unexpected — the behaviour Safari and iOS need.

Every figure in the before/after panel is measured from the encoded file itself: bytes saved, percentage change and the recalculated score. Nothing is predicted after the fact.

Frequently asked questions

Is my image uploaded anywhere?

No. The image is decoded, analyzed, scored and re-encoded inside your browser using the Canvas API and a WebAssembly WebP encoder. Nothing is sent to TryImager servers or any third party, and the optimized file only leaves your device if you choose to download it.

What does the Image Optimization Score measure?

It combines five measurable characteristics of your file: total file size, format efficiency, dimensions versus the width you actually display, bytes per pixel, and general web readiness. Images with transparency also get a transparency category. It is a description of the file, not a search ranking score.

Why does the tool usually recommend WebP?

WebP is supported by every current browser, supports transparency, and typically produces a smaller file than JPEG or PNG at comparable visual quality. If your browser cannot encode WebP natively, TryImager falls back to a libwebp WebAssembly encoder that runs locally.

Will optimizing reduce image quality?

Automatic optimization uses a lossy WebP encode at a quality chosen from your image's characteristics, and may reduce dimensions when the image is far larger than its display size. Compare the previews before and after; if you prefer the original, keep it.

Can optimizing make my file bigger?

Occasionally, for images that are already efficiently encoded. When that happens the report says so plainly and you can keep the original.