Optimize PNG Files in Your Browser
PNG is the go-to format for screenshots, logos and graphics with transparency, but PNG files are often far bigger than they need to be. The PNG Optimizer rebuilds them with a smarter colour palette and recompresses them with oxipng, so they load faster and fit upload limits. It all happens in your browser, and your images never leave your device.
Your image is processed by your own browser and never uploaded. Many online editors send your photo to their servers and delete it later — this one never receives it at all.
Why use PNG Optimizer
- Smaller file mode: reduces the palette to 256, 128, 64, 32 or 16 colours
- Lossless mode: every pixel stays exactly the same
- Keeps transparent backgrounds, including soft edges
- Recompresses with oxipng, a proven open-source PNG optimizer
- Shows the old and new size, and never gives you a bigger file
- Pro: optimize up to 100 PNGs at once and download a ZIP
Popular uses
- Shrinking screenshots before adding them to documentation or a help centre
- Making logos and icons lighter for a website
- Getting a PNG under an upload size limit
- Reducing the size of transparent product cut-outs for an online shop
PNG Optimizer: frequently asked questions
How does the PNG Optimizer make files smaller?
In Smaller file mode it first reduces the image to a palette of up to 256 colours, which most screenshots and graphics need anyway. Then it recompresses the PNG with oxipng, which finds the most efficient way to store the pixels. Lossless mode skips the palette step.
Will my PNG look different?
At 256 colours, screenshots, logos and flat graphics usually look identical. Photos and smooth gradients can show faint banding at lower colour counts; for those, use Lossless, or save the photo as JPG or WebP instead.
Does it keep the transparent background?
Yes. Transparency, including soft, semi-transparent edges, is kept in both modes.
Why didn't my file get smaller?
Some PNGs are already well optimized. If the new file would be bigger, ImageSpark keeps your original instead, so you never end up with a larger file. Choose fewer colours for more savings.
Are my images uploaded?
No. The optimizer runs in your browser on your own device, so your images never leave it.