Is PNG Lossy or Lossless? Complete PNG Compression Guide 2025

PNG is a lossless compression format, meaning it preserves every pixel of your original image perfectly without any quality loss. This makes PNG ideal for logos, screenshots, and graphics with text, but results in larger file sizes compared to lossy formats like JPEG. Learn more about lossy vs lossless compression.

How PNG Compression Works

PNG (Portable Network Graphics) uses lossless compression, which means:

What is Lossless Compression?

When you save an image as PNG:

1. Original data preserved - Every single pixel is kept exactly as it was
2. No quality loss - Image looks identical to original, even after saving multiple times
3. Perfect reconstruction - You can decompress and get back the exact original image
4. Larger file sizes - Because no data is thrown away, files are bigger than lossy formats

PNG's DEFLATE Algorithm

PNG uses a compression method called DEFLATE, which combines two techniques:

1. LZ77 compression - Finds repeating patterns in the image data and replaces them with shorter codes
2. Huffman coding - Assigns shorter codes to frequently occurring data patterns
3. Filtering - PNG applies prediction filters before compression to make the data more compressible

Example: If your logo has a large white background, PNG will compress all those repeating white pixels very efficiently without losing any quality.

PNG vs JPEG: When to Use Which

Here's the practical difference between PNG (lossless) and JPEG (lossy):

File Size Comparison

Logo with text (500x500 pixels):

• PNG: 85KB (perfect quality, crisp text)
• JPEG: 45KB (smaller, but text looks blurry)
• Winner: PNG - text remains sharp and readable

Photography (1920x1080 pixels):

• PNG: 3.2MB (perfect quality but huge size)
• JPEG: 400KB (88% smaller, quality loss barely noticeable)
• Winner: JPEG - much smaller with acceptable quality

Quality Comparison

PNG advantages:

• Text stays perfectly crisp and readable
• Logo colors remain exact
• Transparency support (JPEG doesn't support this)
• No compression artifacts or blur
• Save and edit multiple times without quality loss

JPEG advantages:

• Much smaller file sizes for photos (70-90% reduction)
• Faster loading on websites
• Good enough quality for most photos
• Better for complex images with many colors

Compare different image formats here.

When to Use PNG Format

PNG is the best choice for these types of images:

1. Logos and Brand Assets

Why PNG works best:

• Company logos need perfect colors
• Brand assets must look crisp on all devices
• Text in logos must remain readable
• Transparency needed for logos on different backgrounds

Example: Your company logo with transparent background saved as PNG will look perfect on white website backgrounds, colored banners, and dark footers.

2. Screenshots and UI Elements

Perfect for:

• Software screenshots with text
• UI mockups and designs
• Infographics with text
• Diagrams and flowcharts
• Icons and buttons

Why: Text and sharp lines remain perfectly crisp without any blur.

3. Images Requiring Transparency

Use PNG when you need:

• Transparent backgrounds
• Drop shadows
• Rounded corners with transparency
• Overlay graphics
• Watermarks

Note: JPEG doesn't support transparency at all - PNG is your only choice here.

4. Images You'll Edit Multiple Times

PNG advantage:

• Save and re-edit without quality loss
• Original quality preserved forever
• No cumulative degradation

JPEG problem: Each time you save JPEG, quality decreases slightly.

When NOT to Use PNG

Avoid PNG for these scenarios:

1. Photography and Complex Images

Problem:

• PNG files become massive (3-5MB per photo)
• Slow website loading
• High bandwidth costs
• No visible quality benefit over JPEG for photos

Solution: Use JPEG or WebP for photos instead.

2. Large Background Images

Example:

• Hero section background: PNG = 2.5MB, JPEG = 180KB
• Full-width banner: PNG = 1.8MB, JPEG = 150KB

Better choice: Use JPEG or WebP for backgrounds.

3. Photo Galleries

Reality check:

• 50 photos in PNG = 150-200MB total
• 50 photos in JPEG = 20-30MB total
• Loading time: PNG takes 5-8x longer

Recommendation: Always use JPEG or WebP for photo galleries.

Optimizing PNG Files

Even though PNG is lossless, you can still reduce file sizes without losing quality:

1. PNG Compression Tools

Free tools that work:

• TinyPNG - Removes unnecessary metadata, optimizes compression
• OptiPNG - Command-line tool for better compression
• PNGGauntlet - Windows tool for aggressive optimization

Results: Often 20-50% size reduction without any quality loss.

2. Reduce Colors When Possible

If your PNG has limited colors (like logos):

• PNG-24 (16 million colors): Use for photographs saved as PNG
• PNG-8 (256 colors): Use for simple logos, icons
• Savings: PNG-8 can be 70% smaller than PNG-24 for simple graphics

3. Use Image CDN for Automatic Optimization

How it works:

1. Upload original PNG to CDN
2. CDN automatically optimizes PNG compression
3. Modern browsers get WebP or AVIF (smaller, still lossless)
4. Older browsers get optimized PNG
5. You save bandwidth, users get faster loading

Learn about automatic format conversion.

PNG Technical Details

Compression Ratio

Typical PNG compression ratios:

• Simple logos: 6:1 to 10:1 compression (very efficient)
• Screenshots: 3:1 to 5:1 compression (good)
• Complex photos: 1.5:1 to 2:1 compression (poor - use JPEG instead)

Color Depth Options

PNG supports different color depths:

• PNG-8: 256 colors, smaller files, good for simple graphics
• PNG-24: 16 million colors, larger files, good for complex images
• PNG-32: 16 million colors + transparency, best for logos with shadows

Transparency Support

PNG offers two types:

1. 8-bit transparency (PNG-8): Each pixel is either fully transparent or fully opaque (256 levels)
2. Full alpha transparency (PNG-24/32): 256 levels of transparency per pixel (smooth edges, drop shadows)

Real-World Usage Examples

E-commerce Website

PNG for:

• Product category icons
• Logo in header
• Trust badges and certifications
• Payment method icons

JPEG for:

• Product photos
• Banner images
• Lifestyle photography

Blog Website

PNG for:

• Site logo
• Social media icons
• Custom illustrations with text
• Infographic elements

JPEG for:

• Featured images
• Author photos
• Post thumbnails
• Background images

Common Questions Answered

Can PNG be converted to JPEG without quality loss?

No. When you convert PNG to JPEG, the JPEG compression will add some quality loss because JPEG is a lossy format. However, the quality loss might not be visible to human eyes for photos.

Is PNG better quality than JPEG?

For logos, text, and graphics - yes, PNG is better because it's lossless. For photographs - not really. JPEG quality loss is barely noticeable in photos, and file sizes are much smaller.

Why are my PNG files so large?

Because PNG preserves every pixel perfectly (lossless). For complex images like photos, there's not much repeating data to compress, so files stay large. Use JPEG for photos instead.

Can I use PNG for all images on my website?

Technically yes, but it's not recommended. Your website will load very slowly because PNG files are much larger than needed for photos. Use PNG only for logos, icons, and graphics with text.

Best Practices Summary

Use PNG for:

• ✅ Company logos and branding
• ✅ Screenshots with text
• ✅ Graphics with sharp edges
• ✅ Images needing transparency
• ✅ Icons and UI elements
• ✅ Infographics with text

Use JPEG/WebP for:

• ❌ Photographs and complex images
• ❌ Large background images
• ❌ Photo galleries
• ❌ Hero section backgrounds
• ❌ Author photos and portraits

Quick tip: PNG is lossless and perfect for logos and graphics, but use JPEG or WebP for photos. Most modern websites use a mix of both formats - PNG for UI elements and JPEG/WebP for photography. Let your Image CDN automatically choose the best format based on content.

Understanding compression types helps you make better decisions for website performance.