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FormShrink

Compress PNG Images Online

PNG is the right format for screenshots, logos and graphics with transparency, but full-color PNGs are often much bigger than they need to be. FormShrink compresses PNG files by rebuilding them as palette PNGs: up to 256 carefully chosen colors instead of millions, with smoothing (dithering) so gradients don't band. A typical app screenshot shrinks by half or more, and transparent backgrounds stay transparent.

Images that already use 256 colors or fewer, like most logos and icons, are converted without losing a single pixel. Everything runs in your browser, so your images are never uploaded. Free, with no sign-up.

This page presets the tool: Advanced mode, PNG output at Balanced quality (80) and no size target. Choose Smallest (more compression) for fewer colors, High (best detail) for lossless output, or enter a Target size (KB) under Compression Settings; Reset Settings restores the preset.

Add Images
Drag and drop your images here or click to select files

Drop your images here

Click to select images

Add images and compress them first
Compression Settings
Higher quality means larger file size
80%
80%

Higher values preserve more detail but produce larger files.

Leave blank to let FormShrink decide the optimal size.

EXIF data such as camera details and GPS location is removed automatically

Drag and drop your images here or click to select files
Our Rust + WebAssembly engine compresses up to 10 images per batch without leaving your browser.
Everything happens locally. No uploads, no queue, no waiting for third-party servers.
Supported formats: JPEG, PNG, WebP, GIF, BMP, TIFF
Max file size: 50MB
Max files: 10

JPEG · PNG · WebP support target size compression. Other formats need to be converted first.

How to compress a PNG

  1. Add PNG files

    Drag up to 10 PNG files onto the upload area or click Browse Files. Other formats work too and are saved as PNG.

  2. Pick a quality level

    Balanced reduces each image to a 256-color palette, which is hard to tell apart from the original on screenshots and graphics. Smallest (more compression) uses 128 colors for an even smaller file. High (best detail) keeps every color and only re-compresses the PNG losslessly.

  3. Compress PNG and download

    Click Compress Images and compare the sizes in the results. Download each PNG or use Download All. If a PNG can't be made any smaller, FormShrink gives you back the original file instead of a bigger one.

What PNG compression works best for

Palette compression shines on images with flat areas of color and sharp edges, which is exactly what PNG is used for. In our tests a 347KB app screenshot came out at 147KB and an 18KB transparent logo at 8KB.

Screenshots

Screenshots for documentation, bug reports and tutorials keep sharp, readable text while typically shrinking by half or more, so pages and tickets load faster.

Logos and icons with transparency

Transparent and semi-transparent edges are preserved, so a compressed logo still sits cleanly on any background color. Logos with 256 colors or fewer are compressed losslessly.

Diagrams, charts and UI mockups

Flat colors and thin lines stay crisp in a palette PNG, which makes the result a good fit for slides, wikis and design handoffs.

Photos saved as PNG

A photo saved as PNG does get much smaller as a palette PNG, but JPG is still far smaller at the same visual quality. If you don't need transparency, switch Output Format to JPEG, or use compress JPG.

Tips for smaller PNG files

  • Resize before you share. A 4K screenshot shown at half size in a document wastes most of its pixels, so enter a smaller Width and Height under Resize Image.
  • Crop out unused space. Empty margins and toolbars around a screenshot still take up bytes.
  • Lower quality means fewer colors. The Fine-tune slider goes from 256 colors at Balanced down to 32 colors at its lowest settings, which suits simple graphics but can make gradients look grainy.
  • If a PNG has to fit a size limit, enter a Target size (KB). The tool tries fewer and fewer colors first and only shrinks the image dimensions if that still isn't enough.

Questions about compressing PNG images

Is PNG compression lossless here?

It depends on the image and the quality level. Images with 256 colors or fewer, and any PNG at High (best detail), are compressed without losing any detail. At Balanced, images with more colors are reduced to a 256-color palette with dithering; on screenshots and graphics the difference is very hard to see, while smooth photo gradients may look slightly grainy up close.

Does compressing a PNG keep the transparent background?

Yes. Transparent and semi-transparent pixels are kept in the palette PNG. Transparency is only lost if you switch Output Format to JPEG, which has no alpha channel.

Can my compressed PNG end up bigger than the original?

Not when the input is already a PNG at the same size: if the new file wouldn't be smaller, FormShrink returns the original unchanged, so you never download a bigger PNG. Converting a JPG to PNG is different, since PNG is a larger format for photos; for those, keep JPG output.

Should I convert my PNG to JPG instead?

For photos, yes: a photo saved as JPG is usually several times smaller than the same photo as PNG, even after palette compression. For screenshots, text and logos, stay with PNG, since JPG blurs sharp edges and can't store transparency.

How do I compress a PNG to a specific size, like 100KB?

Enter 100 in the Target size field. FormShrink steps down from 256 colors to as few as 16, and only if that still isn't enough does it reduce the image dimensions until the PNG fits. For photos, JPG output reaches small sizes with much better quality; see compress image to 100KB.

Can I compress PNG files offline?

Yes, once you've added your first image and the tool has loaded. The compression engine runs in your browser rather than on a server, so it keeps working without a connection, and your images are never uploaded.

Other formats and sizes