Private processing
PNG files remain inside the current browser tab and are not sent to an ImageOptimise image-processing server.
Optimise PNG images online for smaller files
Reduce PNG file size privately with Smart palette compression or exact-pixel Lossless optimisation. Preserve dimensions and transparency, process up to 25 images and download the completed batch in one ZIP.
25PNG images per batch25MBmaximum per image2PNG compression modes
Image optimiser
Drop your images and we’ll optimise them automatically
No upload
Drop images here
or choose files from your device
JPEG, PNG, WebP or SVG · Up to 25 images · 25MB per image
Original0 B
OptimisedPending
Space savedPending
Private Files stay on your device
Smart default Smaller PNG files automatically
Original size Dimensions are preserved
Built for graphics and transparency
A smarter PNG optimizer for everyday web assets
Smart mode targets the substantial reductions most people expect, while Lossless mode remains available for workflows that require exact decoded pixels.
Transparency supported
Transparent and semi-transparent content remains supported in both Smart and Lossless modes.
Quality safeguard
A Smart candidate is used only when colour and transparency checks pass and it is smaller than the lossless result.
Batch ZIP download
Optimise one PNG or a batch of up to 25 and collect the completed results in one ZIP.
How to compress an image
From original image to lighter file in three steps
No account, installation or compression expertise is required.
Add your images
Drag SVG, JPEG, PNG or WebP files into the drop area, or browse your device. You can select one image or a mixed batch of up to 25.
Let the browser optimise them
The tool validates each file and automatically uses the tested codec for its format while keeping the decoded pixel dimensions.
Review and download
See the original size, output size and genuine percentage saved. Download individually or choose Download all as ZIP.
Understand PNG optimisation
Choose a smaller Smart PNG or exact-pixel Lossless output
Both modes preserve dimensions and support transparency, but they make different choices about colour data.
Smart palette processing
A quality-checked 256-colour palette targets a much smaller PNG, then OxiPNG removes additional encoding overhead.
Lossless processing
OxiPNG searches for a more efficient representation while preserving every decoded pixel.
Alpha transparency
Transparent edges, shadows and overlays remain supported, which is important for logos and interface graphics.
Dimensions preserved
Width and height remain unchanged. The separate resize tool is available when smaller pixel dimensions are appropriate.
File size and visual quality
Smart compression balances a smaller file with a clear image
Smart mode reduces the colour palette and measures the candidate against the decoded source. It keeps the Smart file only when the quality score and transparency change remain inside the approved safeguards.
Lossless mode changes no decoded pixels and is the appropriate choice for exact brand colours, scientific images or pixel-level workflows. Its saving can be more modest because all original colour values must remain available.
Always review important images at normal display size before publishing. Compression results depend on the image content, source encoder and previous processing history.
Current optimiser safeguards
✓Pixel dimensions are preserved by the current compressor.
✓The input image format is preserved.
✓Transparent PNG and WebP content remains supported.
✓Smart PNG candidates must pass colour and alpha safeguards.
✓Lossless PNG remains available for exact decoded pixels.
✓SVG artwork remains vector content and is never silently rasterised.
✓A larger processed candidate is discarded in favour of the original.
Common uses
Optimise PNG graphics, screenshots and transparent assets
PNG optimisation is useful for interface images, diagrams, logos, screenshots, overlays and photographs where smaller delivery files or transparency matter.
Websites and blogs
Prepare hero images, article photographs and interface graphics before uploading them to a CMS or landing page.
Online stores
Reduce product and category image weight before adding assets to an ecommerce catalogue.
Email and campaigns
Create lighter promotional graphics for campaign production, review and handover workflows.
Reports and presentations
Reduce the source weight of images before placing them into documents, slide decks or downloadable resources.
Portfolio and client delivery
Optimise a batch and provide the completed assets together in one convenient ZIP.
Storage and collaboration
Use smaller working copies where full original encoding weight is not required. Keep original master files separately when needed.
Browser-based privacy
Your current tab owns the temporary image batch
The optimisation code and codecs are delivered to your browser, then supported images are decoded and processed on your device. Image bytes, filenames and job data are not sent to an ImageOptimise image-processing server.
- No account is required to use the compressor.
- Each browser tab maintains its own independent temporary batch.
- Different devices on the same network do not share image sessions.
- Clear All removes the displayed batch; closing the tab ends the session.
Image compression questions
Frequently asked questions
Clear information about formats, privacy, output and batch limits.
Is PNG optimisation lossless?＋
Lossless mode is exact and uses OxiPNG without changing decoded pixels. Smart mode uses quality-focused colour reduction to create a much smaller file when the candidate result passes its safeguards.
Will the PNG optimizer remove transparency?＋
No. Transparent and semi-transparent content remains supported.
Are my PNG files uploaded?＋
No image-processing upload endpoint is used. Supported PNG files are processed inside the current browser tab.
Why did Smart mode use the lossless result?＋
The Smart candidate was not smaller than the lossless file or did not pass the colour or transparency safeguard. ImageOptimise keeps the safer result rather than forcing a weaker output.
Does Smart mode keep every original colour?＋
Not necessarily. Smart mode creates a quality-focused palette to reduce file size while keeping the image visually clear. Choose Lossless when exact colour values are required.
Will PNG optimisation resize my image?＋
No. Pixel dimensions remain unchanged. Use Resize Images when you intentionally want to reduce width or height.
Can I optimise several PNG images together?＋
Yes. Add up to 25 PNG images, each no larger than 25MB, and download results individually or in one ZIP.
Smart and private
Optimise PNG images
Optimise your next PNG batch
Add up to 25 PNG images and use Smart compression for a smaller file or Lossless for exact decoded pixels.