To make a transparent PNG smaller with this tool, first try re-encoding it. If the result barely changes, resize it to the dimensions you actually need. You can also try WebP if the destination accepts that format. Keep PNG or WebP output when transparency matters: JPG output fills transparent areas with white.
Option 1: keep PNG and reduce dimensions
- Add the PNG to the tool above. PNG output is already selected.
- Click Compress images to try re-encoding at the existing dimensions. If this does not produce a smaller file, the tool keeps the original.
- If you can use fewer pixels, enable Resize large images and choose a maximum long edge. For example, 1200 fits an image within a 1200 × 1200 square without changing its proportions.
- Process again and compare the result. Check small lettering, logo edges and translucent shadows.
- Download the PNG and check it against both light and dark backgrounds where it will be used.
Why is the PNG quality slider disabled?
The browser’s PNG encoder does not use the JPEG/WebP quality control. Moving a quality slider would not meaningfully select a smaller PNG in this implementation. This tool is not a dedicated PNG palette-reduction optimizer. A well-optimized PNG at fixed dimensions may stay almost the same size.
PNG encoding is lossless, but resizing changes the pixels. A smaller pixel grid cannot retain every detail from a larger image. Keep your original if you may need a larger version later.
Option 2: try transparent WebP
If your destination accepts WebP, try the converter below with resizing off first. WebP output keeps transparency in this tool, while its quality setting can affect visible detail. Compare the new file size and inspect the edges; a change of format does not guarantee a smaller result.
Keep animation and upload requirements in mind
This tool supports static PNG images and rejects animated PNGs. It does not preserve animation or export an SVG. If an upload form specifically requires PNG, use the PNG result even if a WebP version is smaller.
Format reference: MDN’s image format guide.
Behind the result
Transparency is stored separately from visible colour values. Keep PNG output when lossless encoding is required; the browser encoder may keep an already efficient original.
What does encoding mean?
Decoding turns the bytes in an image file into pixels that a browser can display. Encoding turns pixels back into a file, using the rules of JPG, PNG or WebP. It is not encryption. Our compression and conversion tools decode locally, draw the image onto a canvas and call the browser’s canvas.toBlob encoder. The browser supplies the codec, so results can vary between browsers.
How PNG encoding works
PNG uses reversible filters on pixel rows followed by DEFLATE compression. These steps can represent the encoded pixels without JPEG-style quality loss. PNG ignores the quality slider. This tool uses the browser’s PNG encoder, rather than a dedicated palette-reduction optimiser, so an already efficient PNG may not get smaller. Resizing or colour handling before encoding can still change pixels; lossless encoding does not promise that the whole editing pipeline preserves the original file.
Why the original may be kept
After encoding, the tool compares byte sizes. With Preserve supported metadata selected, when format, dimensions and geometry are unchanged and the new file is not smaller, it keeps the original bytes. This avoids a larger replacement. A retained original also retains its metadata: use the Metadata Remover when privacy cleaning is the goal. ZIP download bundles the files without another lossy image-encoding step.
Where processing happens
Your selected image is processed on your device, without an image upload. Canvas exports are new files and may change embedded metadata or colour information. Keep a master copy for archival work. Animated PNG and animated WebP are rejected; these tools handle static images.
How target-size compression works
Choose 100 KB, 200 KB, 500 KB or a custom decimal-KB limit. For JPG/WebP, the tool tries quality values from your selected maximum down to 10% and refines a successful bracket with a bounded binary search. When you explicitly allow smaller dimensions, it can also try up to eight downsizing steps. PNG ignores quality. Exact resizer dimensions are preserved. Only a measured output within the byte limit is marked Target met; otherwise the smallest tested candidate is marked Above target. This is a bounded search, not proof of a globally optimal result.
Metadata choice
Preserve supported metadata is the default: EXIF dates, camera and GPS fields are copied, with orientation reset after decoding and dimensions updated. PNG text/dates and JPG comments stay within their format. XMP, IPTC and original colour profiles are not transferred; embedded preview links are cleared. Retained metadata is included in target-size measurements. Remove metadata omits source metadata and disables the original-file fallback. Filesystem download dates are separate.
Explore the details: Browser encodingImage formats — MDN