Compress PNG Files
Compress PNG files without giving up transparency. Choose lossless OxiPNG optimisation, which keeps every pixel identical, or a smart 256-colour palette that usually cuts screenshots, logos and graphics to less than half their size. Set a target size in KB if you have a hard limit. Batches are compressed in your browser and never uploaded.
- Runs on your device
- WASM codecs
- Canvas · GPU
- Works offline
Updated
Drop your images here
How to compress a PNG
Step 1: Drop your PNG files on the box above (screenshots, logos, icons, exports).
Step 2: Under Colours, keep 256 for a big saving, or pick All (lossless) to keep every pixel identical.
Step 3: Have a hard limit? Switch Compress by to Target size and type the KB number.
Step 4: Press Compress, compare before and after with the slider, and download.
Good to know
Settings explained
- Colours
- Fewer colours give smaller files. Transparency is kept in every setting.
- All (lossless): OxiPNG only: every pixel identical
- 256: Dithered palette: much smaller
- 128
- 64
- 32
- Target size
- Tries lossless first, then fewer colours, then smaller dimensions until the PNG fits.
- Keep metadata (EXIF)
- Off removes camera details, dates and GPS location — safer when sharing. On keeps them.
Formats
Batch-friendly: add many files and they are processed one after another — if one fails, the rest still finish.
How it runs
- WebAssembly codecs
- Images are encoded with Squoosh-grade codecs (MozJPEG, WebP, AVIF, OxiPNG, JPEG XL). Each codec loads only when you use it.
- GPU canvas
- Pixels are drawn and composited with the GPU-accelerated canvas.
How much smaller will my PNG get?
It depends on the image more than the setting. Lossless optimisation trimmed our test files by 7–22%. Reducing to a 256-colour palette cut them by 61–64%, and fewer colours squeeze a little more out of photos. Graphics with few colours gain the most and look unchanged; photographs saved as PNG show dithering at low colour counts.
| Setting | Transparent logo, 9.5 KB | Text screenshot, 39.3 KB | Photo as PNG, 2.0 MB |
|---|---|---|---|
| All (lossless) | 8.3 KB (−13%) | 30.5 KB (−22%) | 1.9 MB (−7%) |
| 256 colours (default) | 3.7 KB (−61%) | 15.1 KB (−62%) | 722 KB (−64%) |
| 128 colours | — | — | 599 KB (−71%) |
| 64 colours | 3.2 KB (−67%) | 15.4 KB (−61%) | 503 KB (−75%) |
| 32 colours | — | — | 389 KB (−81%) |
How to compress a PNG without losing quality
Choose All (lossless). The image is rewritten with OxiPNG, which searches for a tighter way to store exactly the same pixels: better filters, stronger compression and no wasted metadata. Every opaque pixel is identical to the original and transparency is preserved, so it is safe for icons, UI assets and anything you will edit again.
The saving is modest, usually somewhere between a few percent and a quarter of the file. If the PNG was already optimised, the result would not be smaller, and in that case the tool hands back the original image data with only its metadata removed rather than a bigger file.
Lossless vs lossy PNG compression
Lossless compression stores the same pixels in fewer bytes. Lossy PNG compression, which is what the colour settings do, first reduces the picture to a palette of at most 256 colours and then saves that palette image losslessly. A PNG limited to 256 colours needs one byte per pixel instead of four, which is where the large savings come from.
The palette is chosen from the image itself, and dithering (a fine pattern of mixed colours) smooths gradients so banding is hard to see. Flat graphics, charts and screenshots usually look identical at 256 colours; photos and soft gradients are where you might notice it.
| Your PNG | Setting | Why |
|---|---|---|
| App icons, UI assets, pixel art | All (lossless) | Exact pixels matter |
| Screenshots and diagrams | 256 | Usually looks identical, about 60% smaller |
| Logos and flat illustrations | 256 or 128 | Few colours to begin with |
| Stickers with soft shadows | 256 | Keeps the semi-transparent edge smooth |
| Photos saved as PNG | 256, or switch format | Lower counts show dithering; a PNG to JPG or WebP copy is far smaller |
Why is my PNG file so big?
Because PNG never discards detail. A screenshot with millions of slightly different colours, a photo exported as PNG, or an image saved with 16 bits per channel all store every value exactly. Some apps also write PNGs quickly rather than compactly and add metadata such as colour profiles or text chunks.
Compressing fixes the second problem with lossless optimisation and the first with a smaller palette. If the PNG is a photograph with no transparency, the honest answer is that it should not be a PNG at all: converting it to JPG or WebP will shrink it far more than any PNG setting.
Does compressing a PNG remove transparency?
No. Transparency is kept in every setting. In lossless mode the alpha channel is copied exactly; in palette mode the palette includes transparent and semi-transparent entries, so soft edges and drop shadows stay soft instead of becoming jagged. Our logo test file stayed transparent at 64 colours. Only converting to JPG removes transparency, and this page never does that.
Compressing a PNG to an exact size
Switch Compress by to Target size and type the limit in KB. The tool tries lossless first, then 256, 128, 64, 32 and 16 colours, and if the file still does not fit it scales the image down step by step until it does. The result stays a PNG and stays transparent. Aim for a realistic limit: a large photo saved as PNG may have to shrink a lot in pixels to fit a small number.
Why compress PNG files with ProMedia
- Nothing is uploaded. Files are optimised in your browser, so there is no file-size or file-count cap and no server copy.
- Real lossless option. OxiPNG is offered as a setting of its own, not hidden behind a quality slider.
- Never bigger. A plain compression that would not help returns the original pixels instead of a larger file.
- Free, batch, offline-capable. No account or watermark, and once your first compression has cached the encoders, the page keeps working offline.
Tips & troubleshooting
Website images? A PNG to WebP conversion keeps transparency and is often smaller than any PNG setting; our logo became 4.0 KB as lossless WebP.
Huge screenshots from a high-resolution display: set Max width under Advanced settings to 1920 or 1280 px before compressing.
Need JPG, WebP or AVIF output as well? The general image compressor handles every format.
Form wants a JPG under a KB limit rather than a PNG? Use Compress Image to KB.
Compress PNG FAQ
How do I compress a PNG without losing quality?
Select All (lossless) under Colours and press Compress. OxiPNG stores the identical pixels more efficiently, usually saving a few percent to about a quarter of the size, with transparency untouched.
Why is my PNG file so big?
PNG is lossless, so photos, detailed screenshots and 16-bit images keep every colour value. Some programs also save PNGs without optimisation. A 256-colour palette or converting photos to JPG shrinks them most.
Does compressing a PNG remove transparency?
No. Lossless mode copies the alpha channel exactly, and the palette modes include transparent and semi-transparent colours, so edges stay smooth.
What is the difference between lossless and lossy PNG compression?
Lossless keeps every pixel and only finds a smaller encoding. Lossy PNG compression reduces the image to a palette of up to 256 colours first, which saves far more but changes some colours slightly.
How much can I reduce a PNG’s size?
In our tests, lossless saved 7–22% and a 256-colour palette saved 61–64%. Simple graphics often shrink more; photos saved as PNG shrink most when converted to JPG or WebP instead.
Can I compress a PNG to a specific size in KB?
Yes. Choose Target size, type the KB limit and press Compress. The tool reduces colours and, if necessary, dimensions until the PNG is under the limit, keeping transparency.
Is there a file size limit?
There is no upload limit because there is no upload. Very large photos can exceed what a phone browser can handle: Safari on iPhone and iPad lets a web page edit images of up to about 16 megapixels. There are no daily caps and no watermark.