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JPG and PNG compress images in fundamentally different ways, and picking the wrong one wastes file size or destroys quality. JPG throws away data your eyes barely notice (lossy). PNG keeps every pixel exact (lossless). Here is when each one wins and how to compress both properly.
| JPG (JPEG) | PNG | |
|---|---|---|
| Compression type | Lossy (discards some data) | Lossless (keeps everything) |
| Transparency | ✗ No | ✓ Yes (alpha channel) |
| Best for | Photos, gradients, complex scenes | Logos, text, screenshots, graphics |
| Typical file size | Small (100KB-2MB for web photos) | Large (500KB-10MB for same image) |
| Quality after compression | Slightly reduced (usually invisible) | Identical to original |
| Re-save quality loss | ✗ Yes (degrades each re-save) | ✓ No (lossless every time) |
| Color depth | 8-bit per channel (16.7M colors) | 8 or 16-bit per channel |
| Invented | 1992 | 1996 |
JPG dominates for photographs and complex images with millions of color variations:
PNG is the right choice when exact pixel accuracy matters:
Compress your JPGs and PNGs — the tool auto-detects the format.
Open Image Compressor →| Image Content | Best Format | Quality Setting | Expected Size Reduction | Notes |
|---|---|---|---|---|
| Portrait photo | JPG | 80-85% | 60-70% smaller | Skin tones compress well in JPG |
| Landscape photo | JPG | 80-85% | 60-70% smaller | Complex detail hides artifacts |
| Product photo (no transparency) | JPG | 85-90% | 50-60% smaller | Higher quality for commercial use |
| Product photo (transparent bg) | PNG | 80-85% (lossy PNG) | 40-60% smaller | Must stay PNG for transparency |
| Company logo | PNG | Lossless or 90%+ | 20-40% smaller | Sharp edges need PNG precision |
| App screenshot | PNG | 85-90% | 30-50% smaller | Text must stay crisp |
| Chart or diagram | PNG | Lossless | 20-40% smaller | Clean lines, flat colors = PNG territory |
| Social media photo | JPG | 75-80% | 70-80% smaller | Platforms re-compress anyway |
| Website hero banner | WebP | 80% | 75-85% smaller | Best web format for photos |
| Email header graphic | JPG | 80% | 60-70% smaller | Keep under 200KB for fast email loading |
JPG splits the image into 8x8 pixel blocks, converts color data from RGB to YCbCr (luminance + chrominance), applies a mathematical transformation (DCT) to find patterns, and then throws away the patterns your eyes are least sensitive to. Lower quality = more patterns thrown away = smaller file = more visible artifacts.
This is why JPG creates artifacts around sharp edges. The 8x8 block boundary falls across the edge, and the algorithm struggles to represent both the sharp transition and the surrounding area. On photos with gradual transitions, those 8x8 blocks blend smoothly and artifacts are invisible.
PNG scans each row of pixels, applies a filter to find patterns (like "this pixel is the same as the one above it"), and then compresses the filtered data using DEFLATE (the same algorithm zip files use). No data is discarded. The original pixels can be perfectly reconstructed.
This is why PNG excels at images with large areas of the same color. A logo with a white background has thousands of identical white pixels in a row. PNG compresses these to almost nothing. A photograph with millions of unique pixel values gives PNG very little to work with, which is why PNG photos are so large.
If your images are going on a website, WebP eliminates the JPG vs PNG decision. WebP supports both lossy compression (like JPG) and lossless compression (like PNG), plus transparency. And it produces smaller files than both formats at the same quality.
WebP's limitation: it is a web format. Email clients, print workflows, and some desktop apps do not support it. For anything outside a web browser, stick with JPG or PNG. For a deeper format comparison including AVIF, check our format comparison guide.
The logo looks fine on a white page. But zoom in and you see fuzzy edges, color bleeding, and blocky artifacts around every curve and line. Save logos as PNG. Always. If file size matters, compress the PNG or convert to WebP. Do not use JPG for logos.
A 4000px photo as PNG might be 12MB. As JPG at 90% quality, it is 2MB. The visual difference is invisible at any normal viewing size. You just created a 10MB waste of bandwidth. Use JPG for photos. Use PNG only when you need transparency or exact pixel accuracy.
Someone sends you a JPG. You open it, make a small edit, and save at 80% quality. The quality loss from the original compression plus your new compression stacks. After 3-4 rounds, visible artifacts appear. Always start from the highest-quality source. If you only have a compressed JPG, compress it as little as possible (90-95%) to minimize additional loss.
Compress JPGs and PNGs. The tool picks the right method automatically.
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