1Drop your PNG images into the box above, or pick them from your device — there is nothing to install and no account to create.
2Choose how hard to squeeze: a quality or bitrate target, and optionally smaller dimensions if size matters more to you than detail.
3Start the job and let the workers re-pack the file; your original is never modified in place.
4Compare the new size against the original, then download the compressed PNG file.
Compress PNG FAQ
What do I get back, and can I control the trade-off?
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A single compressed file per input, at a quality or bitrate level you choose rather than a fixed default. If the result is not small enough, changing the dimensions or the duration will do more than pushing the quality slider further down.
How does Compress PNG actually make the file smaller?
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Concretely, every pixel stays bit-exact and the saving is won from a stronger DEFLATE or LZW pass plus palette reduction where the image genuinely has few colours, so a screenshot or a piece of line art shrinks far more than a photograph does. Nothing about it depends on you installing software: the job runs server-side and hands back a finished file.
Is there anything specific to PNG I should know before compressing?
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Yes — there is no quality slider to get wrong — a PNG round-trips bit-exactly, so the only thing edits cost you is file size. It is worth knowing before you overwrite an original you might need again.
What is the most common mistake when compressing PNG images?
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Compressing the same file repeatedly. Each pass on a lossy format is a fresh generation of loss and the savings shrink while the damage accumulates. Go from the original to your target in one step, and keep the original.
What can I upload to Compress PNG?
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PNG, BMP and TIFF are the lossless raster formats this handles directly, and lossy sources (JPG, WebP, GIF) work too if you want them in the same batch. Multi-page TIFFs are detected and handled page by page.
Is there a file size limit on Compress PNG?
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Yes: free accounts process images up to 25 MB each; lossless sources hit that ceiling sooner than photographs do, because nothing has been thrown away yet. If you are over it, converting to PNG first is often enough on its own — a BMP is routinely ten to twenty times the size of the identical image as PNG.
Will Compress PNG lower the quality of my PNG images?
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No. A lossless source round-trips bit-exactly, so unless you explicitly ask for a lossy output format the pixels that come back are the pixels that went in. That is the whole reason to keep working in this family while you are still editing.
Can I run Compress PNG on several PNG images at once?
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Yes — upload the set and they process in parallel under one set of settings. Lossless files are larger, so a big batch is bound by your upload speed rather than by the processing itself.
Why does a EPUB site host Compress PNG?
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EPUB.to is built around the open eBook format — XHTML in a zip, reflowable by design, and readable on hardware nobody has thought about the layout for. A book is a zip full of markup, images and fonts, so almost every job people bring to an eBook site is really a job on one of those things. Compress PNG runs on the same upload and the same account as the conversions because that is where it is needed.
What should I do with the result once Compress PNG is finished?
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The converter on this site moves books between EPUB, MOBI, AZW3, PDF and DOCX, so a title ends up on whatever hardware is actually going to read it. Doing that after Compress PNG means the conversion is made from the version you settled on, not from the one you were still fixing.
Is Compress PNG here the same tool the sibling sites run?
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The engines are shared — the same toolchain, the same workers, the same limits. What a EPUB site adds is a view on reflow: which of these operations a reflowable book genuinely supports, and which ones only make sense on the fixed-layout media inside it. It also starts from one fact about the format this site is named after: the book is a zip of XHTML with a manifest, so the text costs almost nothing and every decision that matters is about the embedded images and font subsets.
Do I need an account, and does anything get kept?
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No account, and nothing is kept: uploads are deleted from the workers shortly after the job finishes, nothing is read and nothing is indexed. Free accounts exist for history and batch size, not for access.
