How to Make a PNG File Smaller (5 Methods That Work)

Your PNG is too big. The upload form rejects it. The email bounces. The page loads slowly. And unlike JPEG, you cannot just drag a quality slider — PNG is lossless, so the standard "lower the quality" approach does not apply the same way.

The good news: there are five reliable methods to reduce PNG file size, ranging from zero-quality-loss optimization to dramatic reductions through format conversion. Pick the one that fits your situation.

Method 1: Lossless PNG Optimization (Zero Quality Loss)

This is the safest option. Lossless optimization reduces file size by improving how the PNG data is encoded — without changing a single pixel.

How It Works

PNG uses DEFLATE compression. Different encoders make different speed-vs-compression tradeoffs. The PNG exported from Photoshop, macOS Screenshot, or Windows Snipping Tool is usually compressed with the fastest (not smallest) settings. A dedicated optimizer re-encodes the same pixel data with better DEFLATE parameters.

Using Pixotter

1. Open pixotter.com/compress.
2. Drop your PNG file(s).
3. Download the optimized files.

Pixotter applies lossless compression automatically. The output is pixel-identical to the input — you can verify by comparing them side-by-side. Typical savings: 20-50% for screenshots and graphics, 5-15% for photographs saved as PNG.

Using OptiPNG (Command Line)

# Install
sudo apt install optipng  # Ubuntu/Debian
brew install optipng       # macOS

# Optimize (overwrites in place)
optipng -o5 image.png

# Batch optimize
optipng -o5 *.png

OptiPNG 0.7.8 (zlib license) tries different filter and compression strategies to find the smallest lossless encoding. The -o5 flag sets a high optimization level (range: 0-7).

Expected Results

Method 2: Reduce the Color Palette

PNG supports color depths from 1-bit (2 colors) to 48-bit (trillions of colors). Most PNGs use 24-bit or 32-bit color — but many images do not need that range. Reducing to an indexed palette (PNG-8, up to 256 colors) can dramatically cut file size.

When This Works Well

• Screenshots with flat colors and solid backgrounds
• Logos and icons with limited color palettes
• Diagrams, charts, and infographics
• UI elements with consistent design system colors

When This Fails

• Photographs (256 colors causes severe banding)
• Images with smooth gradients (banding at color transitions)
• Images with many similar but distinct colors

Using pngquant (Command Line)

# Install
sudo apt install pngquant  # Ubuntu/Debian
brew install pngquant       # macOS

# Reduce to 256 colors (default)
pngquant image.png --output compressed.png

# Reduce to 128 colors (smaller file, more banding risk)
pngquant 128 image.png --output compressed.png

# Batch process
pngquant --quality=65-80 *.png --ext .png --force

pngquant 3.0 (GPLv3) uses a median-cut quantization algorithm with Floyd-Steinberg dithering. The --quality=65-80 flag tells pngquant to find the sweet spot: if it cannot achieve quality 65 or above, it skips the file rather than producing a bad result.

Expected Results

Method 3: Resize the Image

The most effective size reduction: make the image smaller. A 3000×2000 PNG has 6 million pixels. A 1500×1000 version has 1.5 million — 75% fewer pixels to store.

Quick Math

Halving both dimensions reduces pixel count to 25% of the original. File size does not drop by exactly 75% (compression ratios vary), but the reduction is substantial.

Using Pixotter

1. Open pixotter.com/resize.
2. Drop your PNG.
3. Enter the target dimensions or percentage.
4. Download the resized PNG.

Using ImageMagick

# Resize to 50% of original dimensions
magick input.png -resize 50% output.png

# Resize to specific width (height auto-calculated)
magick input.png -resize 800x output.png

# Resize to fit within maximum dimensions
magick input.png -resize 1200x800 output.png

When to Resize

• The image is displayed at a smaller size than its actual dimensions (a 4000px image in a 600px blog column)
• The image is for screen viewing, not printing (screens need far fewer pixels than print)
• The image is a screenshot of a full desktop but only the application window matters — crop first, then resize

Method 4: Strip Metadata

PNG files can contain chunks of non-image data: text comments, creation timestamps, ICC color profiles, software identifiers, and custom application data. These typically add 1-50 KB but can occasionally be larger.

Using ImageMagick

# Strip all metadata
magick input.png -strip output.png

Using exiftool

# Remove all metadata (Perl, works on any OS)
exiftool -all= image.png

Stripping metadata is a small optimization — meaningful for tiny icons where every KB counts, negligible for large photographs. Combine it with lossless optimization for the best result.

Method 5: Convert to a More Efficient Format

If the PNG does not need to stay as PNG (no transparency requirement, no lossless requirement for this particular use), converting to a smaller format produces the biggest size reduction.

Using Pixotter

1. Open pixotter.com/convert.
2. Drop your PNG.
3. Select the output format (WebP recommended for most cases).
4. Download.

Choosing the Right Format

Need transparency? → WebP lossless (26% smaller than PNG, same quality, universal browser support)

Do not need transparency, image is a photo? → JPEG at quality 80-85 (massive size reduction)

Web delivery, maximum compression? → AVIF lossy (smallest possible file)

Need to stay lossless but want smaller? → WebP lossless (always smaller than PNG)

For detailed format comparisons, see PNG vs WebP, Best Image Format for Web, and What is PNG?.

Decision Flowchart

Is the PNG a photograph?
├── Yes → Convert to JPEG (quality 80) or WebP lossy
│         Savings: 70-90%
└── No  → Does it need to stay PNG (transparency, lossless, compatibility)?
          ├── Yes → Lossless optimize first (20-50% savings)
          │         Still too big? → Reduce colors (if flat graphics)
          │         Still too big? → Resize to smaller dimensions
          └── No  → Convert to WebP lossless (26% smaller, keeps transparency)
                    Still too big? → WebP lossy at quality 80+

Most common mistake: Running a photograph as a PNG. A 12 MP photo saved as PNG can be 15-25 MB. The same photo as JPEG at quality 85 is 1-3 MB — with no visible quality difference. Check whether your image needs to be PNG at all before trying to optimize it.

Combining Methods for Maximum Reduction

The methods above are not mutually exclusive. For maximum file size reduction, combine them:

1. Crop unnecessary borders and whitespace
2. Resize to the smallest dimensions you actually need
3. Reduce colors (if the image has few colors and no gradients)
4. Lossless optimize (always — there is no downside)
5. Convert format (if PNG is not required)

Example: A 3000×2000 screenshot PNG at 4.2 MB → crop to content area (2400×1600) → resize to 1200×800 → reduce to 128 colors → optimize → 180 KB. That is 96% smaller, and it still looks sharp on a blog or in a document.

Frequently Asked Questions

Can I make a PNG smaller without losing quality?

Yes. Lossless optimization (Method 1) reduces file size by improving the PNG encoding without changing any pixels. Typical savings are 20-50%. Tools: Pixotter, OptiPNG, or oxipng. The output is visually and mathematically identical to the input.

Why is my PNG file so big?

PNG uses lossless compression, which preserves every pixel exactly. For photographs and complex images, lossless compression produces large files because there are few repeating patterns to compress. For screenshots and graphics with flat colors, PNG is efficient — but the files are still larger than lossy formats like JPEG. See How to Compress PNG for the technical details.

Should I convert my PNG to JPEG to save space?

If the image is a photograph without transparency, yes — JPEG at quality 80-85 will be 70-90% smaller with imperceptible quality difference. If the image has transparency, sharp text, or UI elements, keep it as PNG (or convert to WebP, which handles all of these). See JPG vs PNG for the full comparison.

What is the difference between this guide and the Compress PNG guide?

How to Compress PNG focuses on the compression techniques themselves — how DEFLATE works, lossless vs lossy PNG compression, and tool-specific settings. This guide focuses on the broader problem: "my PNG is too big, what are ALL my options?" — including resizing, cropping, format conversion, and metadata stripping, not just compression.

How do I reduce a PNG to a specific file size (like under 1 MB)?

There is no single setting that targets a specific file size because PNG compression ratios depend on image content. The approach: try lossless optimization first. If still too big, resize to smaller dimensions. If still too big, reduce colors. If nothing works within PNG, convert to JPEG or WebP and use a quality slider to find the target size. See How to Compress Image to 100KB and How to Compress Image to 1MB for target-size guides.

Does reducing colors in a PNG always cause visible quality loss?

Not always. Many screenshots and graphics use only 50-100 distinct colors despite being stored at 24-bit depth (16.7 million possible colors). Reducing to 256 colors changes nothing visible in these cases. The risk appears with photographs, gradients, and images with many subtle color variations — these show visible banding when quantized to 256 or fewer colors.