The best image compressor tool for exact file sizes

ShrinkTo uses a binary-search algorithm that intelligently tries different JPEG quality levels until the output image fits within your target size. We start at a balanced quality, check the resulting file size, and adjust up or down with each pass.

If quality reduction alone is not enough to hit a very small target, we progressively scale down the dimensions while keeping the image as sharp as possible. The whole process usually completes in under a second.

No. ShrinkTo runs entirely in your browser using the HTML5 Canvas API. Your images are never sent to any server. We do not have a backend, a database, or any way to see, store, or transmit your files.

You can verify this yourself by opening your browser's developer tools, going to the Network tab, and watching while you compress an image. You will see zero upload activity.

ShrinkTo accepts JPG, PNG, WebP, GIF, and BMP files as input. The output is delivered as an optimized JPEG by default — JPEG is the most efficient format for hitting strict file-size targets while keeping photos sharp.

Yes — fully and forever free. No signup, no watermarks, no daily limits, and no surprise paywalls. Because all processing happens in your browser, we don't have server costs to recover, so the free tier is sustainable.

Absolutely. ShrinkTo is built specifically for portals with strict file-size requirements. Common use cases include:

Passport applications (20 KB photo, 10 KB signature), UPSC and SSC exam forms (20–50 KB), Aadhaar update portals, state PSC applications, university admissions, NEET/JEE applications, and most other Indian government and exam portals.

Use the custom field to set the exact KB value the portal requires.

Some quality loss is unavoidable when compressing to a strict target — that's how compression works. However, ShrinkTo always uses the highest quality possible that still fits your target size. For most photos compressed to reasonable targets (100 KB and up), the result is visually indistinguishable from the original.

You'll always see a side-by-side preview before downloading, so you can confirm the result looks right.

ShrinkTo accepts source images up to 50 MB. For nearly all practical use cases — phone photos, DSLR exports, scanned documents — this is far more than you'll need.

Three things put ShrinkTo ahead of generic image compressor tools. First, exact KB targeting — TinyPNG, Compressor.io, iLovePDF, and most other compressors give you a quality slider and you guess. ShrinkTo lets you type "50 KB" and lands within 0.5 KB of that target via binary-search compression.

Second, no upload — the compression runs entirely in your browser. Other tools send your file to their servers (which is why they have daily limits). ShrinkTo has no daily limit, ever.

Third, 14 built-in exam presets — SBI Clerk, IBPS, UPSC, SSC, NEET, JEE, GATE, RBI, plus 4 country passport specs. One click sets the right dimensions, KB cap, and format for each.

It depends on what you're doing. TinyPNG is excellent for general-purpose web image compression at default quality. ShrinkTo is the better choice when (a) you need to hit an exact KB target like "must be under 50 KB" — TinyPNG has no target option; (b) you need to compress more than 20 images in a day on the free tier — TinyPNG caps at 20/day; (c) you're handling sensitive images and don't want them uploaded to any third-party server.

Quality-wise the two tools are essentially tied — both use mozjpeg-style compression and produce visually identical output at the same file size. See our head-to-head test of 12 image compressors for measured SSIM scores.

Yes. Once the ShrinkTo page is loaded in your browser, the compression itself works fully offline because everything runs locally in JavaScript and the Canvas API. You can disconnect your network, drop an image in, compress, and download — all without any internet activity.

You'll need internet for the initial page load. After that, the page works offline until you close the tab. We have a PWA manifest, so you can also install ShrinkTo to your home screen for offline access.

Passport photos have specific dimensions (often 35×45 mm at ≤ 240–500 KB depending on country) AND specific file-size limits. Most generic image compressor tools only handle file size, leaving you to resize separately. ShrinkTo handles both in one step: pick "Passport — USA" or "Passport — India" from the Portal preset dropdown above the dropzone, drop your photo, and the output is sized and compressed to that country's exact spec.

Supported as built-in presets: USA, UK, India, Schengen passport. For other countries, use the Custom KB target and look up the dimension requirement on your country's official passport portal.

Yes — ShrinkTo's free WordPress plugin brings the same browser-native compression engine inside the WordPress admin. Compression happens in your admin browser tab, not on any vendor server, so there's no API key, no monthly limit, and no third-party data processing. Other WordPress image compressor plugins (Smush, ShortPixel, Imagify, EWWW) all route images through their own servers — ShrinkTo is the first that doesn't.