How does exact-size optimisation work?

The tool runs a bounded binary search on quality for your chosen formats. If Allow resizing is on and the target is still too small, it progressively reduces dimensions while preserving aspect ratio. A result is only marked successful when it is at or under the effective target.

Does this create lossless output?

No for JPG, WebP and AVIF — those are lossy. PNG output is only realistic for simple graphics. Use the preview to judge the quality/size trade-off.

Why can't I hit the target while preserving dimensions?

At the original pixel size, even the lowest practical quality may still exceed your limit. Enable Allow resizing, raise the target, or switch format.

Are my images uploaded to a server?

No. Your image files are processed locally in your browser and are not uploaded to PictureConvert. See our privacy policy for website analytics.

Is this image tool free to use?

Yes. You can use this tool directly in your browser for free, without account creation or hidden upload limits.

Do my files leave my device?

No. Processing happens locally in your browser, so your image files stay on your device and are not uploaded to PictureConvert. Website analytics (not image contents) are described in our privacy policy.

Exact File Size Image Compressor — free & private

Compress images to an exact KB/MB limit locally in your browser

CompressProcessed locallyInstantNo account

Local browser workflow

Compress an image to an exact file-size limit without uploading it. Choose presets like 50KB or 200KB, optional safety margins, and preserve dimensions or allow resizing. Everything runs on your device — free, no account required, and image files are not uploaded to PictureConvert. Related: Compress JPG, Bulk Image Processor, and Resize Image.

Drag & drop your image

or click to browse files

Supports: JPEG, PNG, WEBP, AVIF (max 100MB)

Processed locally
No image upload
No account required
Images not stored by PictureConvert

After you compress

Strip metadata before sharing, resize for social crops, or optimize for web delivery if the image is heading to a site.

Resize Image Remove EXIF Web Optimizer

Updated for 2026

Popular upload limits

Need a dedicated page for a common ceiling? Open a preset landing — each one embeds this same optimiser with the target preselected.

Choose a target: 50KB · 100KB · 200KB · Under 1MB

Exact file-size compression, locally

Smart Optimizer aims for a hard upper limit — for example 50KB or 200KB — by searching quality (and optionally dimensions) in your browser. Image files are not uploaded to PictureConvert. Lossy formats such as JPG, WebP and AVIF trade detail for size; they are not lossless.

Compression versus resizing

Preserve dimensions only changes format and quality. Pixel width and height stay the same. Allow resizing tries that first, then reduces dimensions while keeping aspect ratio if the target is still out of reach. Tiny limits (for example 20KB on a large photo) often require smaller dimensions.

Why PNG files can remain large

PNG is excellent for sharp graphics and transparency, but photographs and detailed PNGs compress poorly compared with JPG or WebP. Transparent PNGs usually need WebP (to keep alpha) or JPG with a background colour. If you force PNG output, the tool may still fail a strict target — that is a format limit, not a bug.

When JPG, WebP and AVIF fit

JPG — widest support for photos and upload forms.
WebP — often smaller than JPG; can keep transparency.
AVIF — typically strongest compression when the browser supports encoding.

Safety margins for upload limits

Platforms sometimes reject files at the exact stated limit after their own re-encoding. A 5% or 10% margin aims slightly under your requested target. The result panel always shows both the requested and effective targets.

Metadata and browser limits

Re-encoding strips most EXIF metadata. For deliberate removal, use Remove EXIF. Very large images are capped for memory safety before searching. Encoding support for AVIF/WebP depends on your browser.

Worked examples

Passport / form photo → 50KB: use Compress to 50KB with Allow resizing. If quality looks soft, crop tighter before retrying.
Email attachment → 200KB: open Compress to 200KB or stay here with a safety margin so the attachment stays under the mailbox cap.
Under 1MB for a portal: try Compress under 1MB with the built-in margin, or set a custom target on this page.

Updated July 2026

What this tool does

This tool searches quality (and optionally dimensions) to land at or under your effective file-size target using JPG, WebP, AVIF, or carefully limited PNG. It is for hard upload limits — not lossless archiving. For single-format quality sliders, try Compress JPG.

Trust and privacy are built into the workflow. Nothing leaves your device during processing, and there is no account setup. That makes it suitable for personal photos, client assets, product shots, and everyday creative work.

How to compress images

Upload or drag your file into the tool above.
Choose output settings such as quality, size, or page options.
Preview the result before you download.
Download the finished file for web, email, print, or sharing.

Tip: start with balanced quality settings rather than maximum compression so detail stays intact for web and sharing.

Key benefits

Use a 5–10% safety margin when platforms re-encode after upload
Tiny targets on large photos usually need Allow resizing
Prefer WebP/AVIF when supported; JPG for maximum compatibility
Transparent PNGs often stay large — convert to WebP or flatten to JPG
Re-encoding removes most EXIF; use Remove EXIF when that is the goal

Privacy note: no files leave your device. All compress steps run locally in your browser.

Exact-size vs standard compress

If you’re using Smart Optimizer, you’re usually trying to meet a specific upload size limit.
Feature	Smart Optimizer	Standard compress
File size goal	Hard upper limit	Quality slider
Resize fallback	Optional	Separate tool
Safety margin	Built-in	Manual guess
Success rule	Must be ≤ target	Best effort

Common use cases

Use this when a form, email system, or CMS enforces a maximum size (for example 50KB or 1MB). For many files at once, use Bulk Compressor. To change pixels without a size target, use Resize Image.

After you finish, continue with related PictureConvert tools if you need another conversion, compression pass, crop, or metadata step — all without leaving the browser.

FAQs

Reviewed by the PictureConvert team

Last reviewed July 16, 2026. This page is maintained so recommendations stay practical and current for Smart Optimizer, with a focus on private, browser-local processing.