Compress PNG Portable Network Graphics Free Online Secure
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Two different ways of making a file smaller
There are only two ways to make a file smaller, and they are not alike. The first is to find repetition and write it down once instead of a thousand times — the method of zip, of PNG and of the streams inside a PDF. Nothing is lost; the original comes back bit for bit. The second is to decide that some of the information was not worth keeping, and this is what JPEG does with a photograph: it discards the detail the eye is least likely to miss. The first method has a hard limit, because there is only so much repetition to find. The second has no limit at all — you can go on discarding until nothing recognisable is left — which is why it comes with a quality setting and the first does not.
Where you need it
An attachment that will not fit the mail server's limit; a portal that rejects anything over a few megabytes; a website where every image is downloaded by every visitor; a phone running out of space; an archive of scans where the same document occupies ten times what it needs. Compression is almost always about somebody else's constraint rather than your own preference.
Questions people ask
How small can I go before it starts to look bad?
For photographs, surprisingly far. Dropping a JPEG to around three quarters of its original quality typically removes more than half the file and leaves nothing visible at normal viewing size. Below about half quality, edges start to show a faint halo and flat areas become blotchy, first in skies and skin. The honest test is to look at the result at full size before sending it, since the damage is invisible in a thumbnail and permanent once saved.
Why did compressing my PNG barely help?
Because it was probably already compressed, and because PNG never discards anything. The format finds repetition, and a photograph saved as a PNG has very little repetition to find, which is also why it was so large to begin with. If the image is a photograph, converting it to JPEG will shrink it enormously. If it is a screenshot, a logo or a diagram, it is already near the smallest it can be without losing something.
Does the file lose quality?
It depends on what the two formats can hold. Converting between formats that store the same thing — a PNG to a BMP, a WAV to a FLAC — loses nothing. Converting into a format that throws information away to save space, such as JPEG or MP3, loses a little every time, and converting back does not bring it back. Where a choice exists, this page errs towards keeping the original quality rather than making the smallest file.
Is my file uploaded anywhere?
No. The conversion happens inside your browser, on your own machine; the file never leaves it and there is no server here that could receive it. That is why a large file is limited by your own memory rather than by an upload, and why nothing you convert can appear in anybody's logs — including ours. The audio and video tools do fetch their conversion engine from this site the first time you use them, some thirty megabytes once; after that the work still happens entirely on your machine.
Why people compress PNG files
PNG is a generous format. It keeps every pixel exactly as it was drawn, which is perfect for screenshots, logos, diagrams and anything with sharp edges, and which also makes the files heavy. A full-screen screenshot on a modern display can easily be three or four megabytes; a large graphic may be ten. When such a file has to go in an email, onto a web page or through an upload form with a size limit, the weight becomes a problem. That is the moment people look to compress PNG files: they want a lighter file that still looks right for the job it has to do.
The usual reasons are practical. A page that loads slowly because its images are too big. A support ticket system that rejects attachments over a few megabytes. A phone that is full of screenshots. A presentation that has grown to a hundred megabytes because of a few oversized pictures. In each case, a sensible reduction in size solves the problem without anyone noticing a difference on screen.
This page lets you compress PNG files entirely in your browser. The image never leaves your device, which matters for screenshots that show private information and for unreleased designs. Below you will find how the size is reduced, what is preserved, what to expect from a lossless format, and how to choose a setting.
How the size is reduced
You pick a resolution
To compress a PNG here, you choose a resolution, and the tool produces a smaller picture at that setting. A lower resolution means fewer pixels, and fewer pixels mean a smaller file. This is the dependable way to shrink a PNG, because the format does not throw away detail inside the pixels it keeps. What you control is how many pixels there are.
Transparency and proportions stay
When you compress PNG files this way, transparency is kept. A logo with a see-through background still has a see-through background. The proportions are kept too: a wide picture stays wide, a square stays square, and nothing is stretched or cropped. The picture is simply drawn with fewer pixels.
The printed size is preserved
The size the image would print at is kept as well. Only the pixel count changes. If you printed the image on a page, it would cover the same area as the original, with a coarser grid of dots. On screens, where size follows pixels, the picture will appear smaller at actual size, which is exactly why the file is lighter.
Why pixel count is what matters
A PNG's size follows the number of pixels it holds, more or less. An image of 3000 by 2000 pixels holds six million; at 1500 by 1000 it holds one and a half million, a quarter as many. Because file size tracks pixel count closely, halving the width and height reduces the file to roughly a quarter. That is why picking a lower resolution is such an effective way to compress PNG files.
What to expect from a lossless format
PNG stays lossless
Here is the key thing to understand: PNG is a lossless format, and it stays lossless when you compress it here. Nothing inside each pixel is blurred or approximated. The saving comes only from having fewer pixels. That is different from JPG, where the format itself can trade detail for size. With PNG, you reduce size by reducing pixels, and that is all.
Photographs shrink far more as JPG
A photograph saved as PNG is much heavier than the same photograph saved as JPG, because PNG preserves every subtle shade while JPG discards the ones the eye will not miss. If your PNG is really a photo, you will get far better savings by converting it. Use the PNG to JPG converter and then, if needed, compress the JPG. For screenshots, diagrams and logos, stay with PNG, because JPG blurs sharp edges and flat colour.
How to tell which one you have
Look at the picture. If it is a photograph of a real scene, with gradual colour changes and no sharp outlines, JPG will serve it better. If it is a screenshot, a chart, a logo or a drawing with clear edges and flat areas, PNG is the right format, and reducing pixels is the right way to make it smaller.
What is lost
Fewer pixels, less fine detail
Reducing the resolution means the picture has fewer dots to describe it. Fine lines may become slightly softer and tiny text may become harder to read. At sensible settings you will hardly notice on a screen, but if your image contains small text, check the result at the size it will be read.
Detail cannot be brought back
A higher resolution setting cannot restore pixels that are gone. If you compress a PNG and later need the detail back, you must return to the original. So keep the original safe, and always compress from it.
What a PNG is, and why it is heavy
PNG stands for Portable Network Graphics. It stores an image as a grid of coloured dots and compresses the data without discarding anything, so the picture you open is bit for bit the picture that was saved. It can hold transparency, which is why logos, icons and interface graphics so often come as PNG. The price of this exactness is size. Where a JPG may drop subtle shades to save space, a PNG keeps every one of them, and a detailed full-screen image can run to several megabytes.
That is why people compress PNG files in the first place. The format is doing its job faithfully, but the job is heavier than most uses require. When you compress PNG files by reducing the resolution, you ask for fewer dots, and the file lightens in proportion, while every remaining dot is still stored perfectly.
PNG compared with JPG, briefly
JPG is lossy and made for photographs; PNG is lossless and made for graphics. Neither is better in general. A screenshot saved as JPG looks smudged around the text; a photograph saved as PNG is several times larger than it needs to be. Choosing the right format for the picture is half the battle, and compressing is the other half.
A workflow for screenshots
Screenshots are the most common PNG files people need to shrink, and a little discipline makes the result much better. Start by capturing only what matters: most tools let you select a region, so you can leave out toolbars and clutter, which also reduces the pixel count before you even begin. If your display is very high-resolution, remember that the screenshot has as many pixels as the screen, far more than a reader needs.
Then compress PNG files to the width at which they will actually be read. A help article might show images at eight hundred pixels wide; a document at around a thousand. Anything beyond that is weight without benefit. Check that small text in the screenshot is still legible at the reduced size, since that is the first thing to suffer when you go too small.
Annotate before you compress
If you plan to draw arrows or boxes on a screenshot, do it first, at full size, and compress PNG files afterwards. Annotations become part of the image and shrink with it. Marking up a reduced image is possible, but lines drawn on a small picture can look chunky when it is viewed at its natural size.
Sensitive details
Screenshots capture whatever is on screen: names, email addresses, tokens, account numbers. Before you share a compressed copy, look for anything private and cover it. Reducing the size does not hide details; it only makes them smaller. Because the work happens on your own device, you can compress PNG files, check them and still decide not to send anything.
Graphics, logos and transparency
For logos and cut-out graphics, the right approach is to compress PNG files to the size at which they are displayed and to keep a large master copy for any future use. Transparency is preserved, so a compressed logo sits cleanly on any background. After compressing, place the result on a coloured background and look at the edges, because a soft edge that looked fine on white can show a fringe on a dark colour.
If you have a logo that you need at many sizes, consider whether a scalable version would serve better. A drawing stored as vectors can be shown at any size without loss. Converting PNG to SVG traces the shapes for simple flat-colour artwork, with the limits that tracing always has, and avoids the need to keep several PNGs of different sizes.
Icons and small graphics
Small PNGs rarely need compressing. If an icon is a few kilobytes, there is nothing to gain. The savings come from large images: screenshots, banners, backgrounds, diagrams and posters. Compress PNG files where the weight is, not where it already is negligible.
How to compress PNG files here
Add your image
Drop the PNG onto the page or pick it from your device. It is read inside your browser and is not uploaded.
Pick a resolution
Choose the setting that matches the use: a moderate one for an email or a form, one that matches the display width for a web page, a larger one if the image will be printed.
Compress and compare
Press the button and download the smaller file. Open it beside the original at the size you will use. If it looks right, you are done; if it looks too soft, repeat from the original with a higher setting.
Choosing a setting for your purpose
Screenshots for support and documentation
Screenshots of a large display are bigger than they need to be. Reducing them to the width at which they will be read, perhaps a thousand to fifteen hundred pixels, keeps text legible and cuts the size sharply.
Logos and graphics for websites
A logo usually appears at a few hundred pixels. A version several times larger is wasted bytes. Compress PNG files like this to the size they are displayed at, keeping a larger copy for print.
Images with transparency
Transparency is preserved, so compressed logos and cut-out graphics still sit cleanly on any background. Check the edges on a coloured background after compressing, to be sure they look right.
Questions people ask before compressing
Will the picture look worse?
Slightly, at most, at sensible settings. Fewer pixels means less fine detail, but on a screen you will rarely notice.
Is the quality loss from compression?
Not in the usual sense. PNG stays lossless. The only change is that there are fewer pixels.
Is my image uploaded?
No. Everything runs in your browser and the image never leaves your device.
What about photos and BMP files?
Photos shrink far more as JPG, so use compress JPG for them. For BMP files, compress BMP turns them into much smaller PNGs.
Who needs to compress PNG files
Web designers and bloggers
Pages load faster with right-sized images, which helps visitors and search rankings alike.
Support and documentation teams
Screenshots go into tickets and manuals. Reducing them keeps attachments small and pages light.
Anyone short of storage
A folder of screenshots can reach gigabytes. Reduced copies take a fraction of the space.
Common mistakes
Using PNG for photographs
Photographs are far smaller as JPG. Convert before compressing.
Deleting the original
You cannot restore pixels later. Keep the full-size file.
Making text unreadable
Reducing a screenshot too far makes small text illegible. Check the result at reading size.
Related tools
To put images into a document, use PNG to PDF. For a smaller file on a website, convert PNG to WebP. If a picture is sideways, rotate the PNG first, and to label it, add a watermark. For drawings that must stay sharp at any size, PNG to SVG traces the shapes.
When to compress PNG files, and when not to
Compressing is right when an image is bigger than its purpose needs: an email, a web page, a form, a chat. It is the wrong move for artwork you may need to print large, edit heavily or reuse at many sizes, in which case keep the full-size original and make a smaller copy only for sharing. And it is pointless if the file is already small: a PNG of a few dozen kilobytes has little left to give.
For the common cases, such as screenshots, website graphics, documentation images and storage clean-ups, it is quick, private and effective to compress PNG files in the browser. Your original is never changed, so you can come back and compress PNG files again at a different setting whenever you like.
Batches of images
If you have many images to reduce, compress PNG files one at a time and keep the originals in a separate folder. Use the same setting for all of them so that the results look consistent. Try one first and check it at the size you will use, so you do not have to redo twenty of them.
Combining with other steps
If your images are going into a document, compress them first and then place them in the PDF with the PNG to PDF converter, which keeps their pixels as they are. That gives you a lighter document without any further loss. If they are going on a website, you can also try converting the PNG to WebP, which often gives a smaller file still.
Large images and slow devices
Everything runs on your own device, so very large images depend on its memory. A typical screenshot is no trouble. A huge poster-sized PNG may be slow on an older phone. If it struggles, give the browser a moment and avoid switching to other apps while it works.
Checking the result properly
After you compress PNG files, open the result at its actual display size, not zoomed in. Zooming in will always show softness; what matters is how it looks where it will be used. If it looks right there, the compression has done its job, and you can stop. If it looks soft, try a higher setting from the original.
Your image stays on your device
The compression happens locally. Your image is read by your own browser, reduced there and handed back. Nothing is uploaded, so there is no copy on a server and no one else who could see it. For screenshots with private information and unreleased designs, that is the safe way to compress PNG files.
A worked example
Say you have a screenshot of 3000 by 1800 pixels and 4 megabytes, and a support form that accepts at most 1. You drop it here, pick a resolution that brings the width to about fifteen hundred pixels and press the button. The result is a few hundred kilobytes, the same shape, with transparency intact and text still readable. You attach it and the form accepts it. The original stays on your computer.
A simple routine to compress PNG files well
Decide where the image is going and how wide it needs to be. Keep the original safe. Compress PNG files once, from the original, at the smallest setting that still looks right, and check text at reading size. Then send, upload or publish the small copy. This routine takes a minute and works whether you compress PNG files once a month or every day, and it keeps your full-size artwork intact for the day you need it.
Before you close the page
Check that you downloaded the smaller file, that it looks fine at the size you will use, and that you kept the original.
Summary
To compress PNG files here, drop the image, pick a resolution and download the result. Transparency, proportions and the printed size are kept. PNG stays lossless, so the saving comes only from having fewer pixels, and photographs shrink far more as JPG. Nothing leaves your device.