Compress Images Online

How to compress an image (it takes about 10 seconds)

We're not going to insult you with a 12-step tutorial. Here's the whole thing.

What actually happens when you compress an image?

Image compression reduces file size by discarding information your eye probably won't notice anyway. For JPG files, this mostly means reducing color detail in areas where colors are similar. A blue sky with subtle gradients can have a lot of redundant information — compression removes the redundancy and your eye still sees a blue sky.

PNG works differently. It uses lossless compression, meaning no image data is thrown away. PNG files can still be reduced in size by optimizing how the data is encoded internally, but you won't see the same dramatic file size reductions you get with JPG. If file size matters a lot, converting your PNG to WebP first is usually a smarter move.

WebP is Google's format and it's genuinely good. Same visual quality as JPG at roughly 25-35% smaller file sizes. All modern browsers support it. If you're building a website, you probably want WebP. If you need JPG for an email or some specific system, stick with JPG.

What quality setting should you actually use?

The quality slider goes from 10 to 100. At 100, you're doing almost nothing. At 10, your image will look like it went through a cheese grater. The useful range for most people is 70-90.

For website images, 80% is a reliable choice. You'll cut file size by 50-70% compared to an uncompressed photo and the visual difference is hard to spot unless you zoom in on text or fine detail. For thumbnails and social media previews, you can even push to 70% without issue.

Print? Don't use this tool for print. Or if you do, use 95%+. Printed images require much higher quality than anything displayed on screen.

Why compress images at all?

The main reason is page speed. Large images are the number one cause of slow websites. Google cares about this, users care about this, and your hosting bill cares about this. A 4MB product photo could be 400KB with the right compression. That's 10x less bandwidth, 10x faster load time.

But it's not just websites. Email attachments, uploading to forms, sharing in Slack or Teams — most platforms have file size limits and smaller images just work better everywhere.

Measured: what each quality setting costs and saves

We saved twelve of the illustrations used on this site as JPEG at every common quality setting, then measured the total size and how close each result stayed to the original. Fidelity is measured in decibels across all the images together: above about 40 the difference is invisible, and below about 35 damage usually shows.

Two things stand out. Going from 100 to 90 removed about 62 percent of the file while staying well inside the invisible range. And below about 70 the savings flatten out while the damage keeps growing: going from 70 all the way down to 50 saved fewer than 6 more points. The sweet spot for photos sits between 75 and 90.

Check it with your own eyes before downloading

Numbers only go so far, so every compressed image here comes with a before and after slider. Drag the divider across the picture to compare the original and the compressed version at full size, paying attention to faces, text and smooth gradients like skies, which show compression first.

Try WebP for a bigger drop

The output switch changes the format as well as the quality. WebP produced the same measured quality as JPEG in about a third fewer bytes across the same twelve images, and it keeps transparency. Every current browser displays it, so for images on a website it is usually the better choice. PNG files in particular barely shrink as PNG, and drop dramatically as WebP.

Compress a whole folder

Drop as many images as you like at once. Each one is compressed on your device, shown as a thumbnail with its saving, and the whole set downloads together as a ZIP. If an image comes out no smaller than the original, the studio tells you, and you should simply keep the original.

Frequently asked questions