Compress PNG Images Online Free
Shrink PNG file sizes by up to 70% using intelligent palette optimization. Converts 24-bit PNGs to optimized 8-bit palette PNGs — transparency is fully preserved. Perfect for screenshots, logos, and graphics.
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Max file size: 25MB
How PNG Compression Works
Our PNG compressor uses palette optimization to dramatically reduce file sizes. It converts 24-bit true color PNGs — which can represent up to 16.7 million colors — into 8-bit palette PNGs that use a carefully selected set of up to 256 colors.
For most screenshots, logos, and graphics, 256 colors is more than enough to represent the image faithfully. The visual difference between the original and the compressed version is nearly undetectable to the human eye, yet file sizes typically drop by 50-70%.
Transparency is fully preserved during this process. The alpha channel is maintained in the optimized palette, so your transparent PNGs remain transparent after compression.
PNG vs JPG: When to Use Each
| Image Type | Best Format | Why |
|---|---|---|
| Photographs | JPG | Lossy compression is ideal for smooth gradients and complex color transitions |
| Screenshots | PNG | Sharp text edges are preserved without compression artifacts |
| Logos & icons | PNG | Transparency support and flat colors compress efficiently |
| Graphics with text | PNG | No compression artifacts on sharp text edges |
| Product photos on white BG | Either | JPG produces smaller files, PNG gives crisper edges |
| Illustrations | PNG | Fewer colors means better palette compression |
What Images Compress Best?
- Screenshots and UI captures — often use 256 colors or fewer, making them ideal candidates for palette optimization.
- Logos and icons — flat color fills compress extremely well with palette optimization.
- Diagrams, charts, and infographics — typically use a limited color palette already.
- Graphics with large areas of the same color — solid backgrounds and flat design elements compress efficiently.
Photos with millions of unique colors don't benefit much from PNG palette optimization — use JPG compression for photographs instead.
Frequently Asked Questions
- How does PNG compression work?
- Our tool uses palette optimization to reduce 24-bit PNGs to 8-bit (256 color) PNGs. This can reduce file sizes by 50-70% while keeping the image looking nearly identical.
- Will my transparent PNG stay transparent?
- Yes, transparency is preserved during compression. Alpha channel information is maintained in the optimized palette.
- When should I use PNG vs JPG compression?
- Use PNG compression for images with text, logos, screenshots, or transparency. Use JPG for photographs and complex images with gradients.
- What is the difference between 24-bit and 8-bit PNG?
- 24-bit PNGs store up to 16.7 million colors, resulting in large files. 8-bit PNGs use a palette of up to 256 colors, which is enough for most graphics and produces files 50-70% smaller.
- Will PNG compression affect my logo quality?
- For logos and graphics with flat colors, palette optimization produces visually identical results at much smaller file sizes. The tool is specifically designed for this use case.
- Can I compress PNG images with transparency?
- Yes, transparency is fully preserved during compression. The alpha channel is maintained in the optimized palette, so your transparent areas remain transparent.