PNG vs JPG
PNG and JPG are the two most common raster image formats on the web. Both store pixels, but they use completely different compression strategies. PNG is lossless and supports transparency; JPG is lossy and optimized for photographs. Choosing the wrong format wastes bandwidth, blurs fine detail, or produces files that are far larger than necessary.
This guide compares PNG and JPG side by side—how they compress data, where each format shines, and when to convert between them using free browser tools.
Quick Comparison Table
| Feature | PNG | JPG / JPEG |
|---|---|---|
| Compression | Lossless (DEFLATE) | Lossy (DCT-based) |
| Transparency | Yes (alpha channel) | No |
| Best for | Graphics, UI, screenshots, logos | Photos, complex gradients |
| Typical file size | Larger for photos | Smaller for photos |
| Color depth | Up to 48-bit (PNG-48) | 8-bit per channel (24-bit RGB) |
| Animation | APNG (limited support) | No (use GIF/WebP instead) |
| Editing tolerance | Excellent—no generation loss | Poor—each save degrades quality |
| Browser support | Universal | Universal |
| Common extensions | .png | .jpg, .jpeg |
Key Differences
Compression philosophy
PNG uses DEFLATE compression—the same algorithm behind ZIP files—on filtered image data. Because nothing is discarded, you can open, edit, and re-save a PNG indefinitely without quality loss. JPG applies a discrete cosine transform (DCT) that removes high-frequency detail the human eye barely notices. The trade-off is dramatic: a 4 MB photo might shrink to 400 KB, but fine edges and text can develop visible artifacts.
Transparency and layers
PNG stores an optional alpha channel, making it the default choice for icons, logos, and UI elements that sit on variable backgrounds. JPG has no alpha support; any transparent areas must be flattened to a solid color before export.
Color and bit depth
PNG supports palette (indexed) and true-color modes, including 16-bit per channel for high-dynamic-range workflows. Standard JPG is limited to 8 bits per channel. For everyday web photos that is sufficient; for medical imaging or professional print pipelines, PNG or TIFF may be safer intermediate formats.
File size patterns
For photographic content, JPG is almost always smaller. For flat graphics—charts, diagrams, screenshots with large solid-color regions—PNG often wins because DEFLATE excels at repetitive data. A screenshot of a code editor might be 800 KB as PNG and 1.2 MB as JPG with visible ringing around text.
Generational loss
Every JPG re-save introduces new artifacts—a phenomenon called generational loss. If you receive a JPG, edit it, and export again as JPG, quality drops even at maximum settings. PNG avoids this trap. Professional workflows keep masters in RAW, TIFF, or PNG and only export JPG as a final delivery step for web or email.
When both formats fail
Modern formats address gaps in the PNG/JPG dichotomy. WebP supports lossy and lossless modes plus alpha at smaller sizes. AVIF pushes compression further with better HDR support. JPEG XL aims to replace both legacy formats but browser adoption is still uneven in 2026. Treat PNG and JPG as universal fallbacks while experimenting with next-gen codecs for performance-critical pages.
When to Use PNG
- Logos and brand assets that need crisp edges and optional transparency.
- UI icons and interface graphics displayed on light or dark themes.
- Screenshots and documentation images where text legibility matters.
- Images with hard edges—line art, charts, pixel art, maps.
- Work-in-progress assets you will edit multiple times before final export.
- Small images with few colors where PNG-8 palette mode keeps files tiny.
When file size is critical but you still need transparency, consider exporting to WebP or AVIF after PNG—many modern browsers support lossy transparency at a fraction of PNG size.
When to Use JPG
- Photographs from cameras or phones destined for web galleries.
- Hero banners and background images where slight softness is acceptable.
- Email attachments and thumbnails where bandwidth is limited.
- Social media uploads that re-compress anyway—starting with a lean JPG reduces double-compression damage.
- Large image libraries where storage and CDN costs add up.
A quality setting between 75 and 85 usually balances size and visual fidelity for web photos. Below 60, blocky artifacts become obvious; above 90, file size climbs quickly with diminishing returns.
E-commerce and product photography
Online stores standardize on JPG for product galleries because shoppers browse dozens of images per session. Consistent 80% quality JPGs at 1200 px width keep catalog pages fast. Use PNG only for logos, trust badges, and overlays with transparency.
Email and messaging
Email clients have inconsistent image support but universally render JPG. Keep inline images under 100 KB when possible—many mobile users on metered plans appreciate lean attachments. PNG screenshots in support tickets are fine when text clarity matters more than byte count.
Technical Deep-Dive
How PNG compression works
Before DEFLATE runs, PNG applies a filter step to each scanline—Sub, Up, Average, or Paeth—so adjacent pixels are encoded as differences rather than absolute values. This preprocessing dramatically improves compression on gradients and solid fills. PNG chunks (IHDR, IDAT, IEND, and optional ancillary chunks like tEXt or iCCP) wrap the compressed stream in a well-defined container format specified by the W3C.
How JPG compression works
JPG splits the image into 8×8 blocks, applies DCT to each block, quantizes coefficients using a quality-controlled matrix, then entropy-codes the result. Chroma subsampling (often 4:2:0) stores color at half resolution relative to brightness, exploiting human vision’s lower sensitivity to color detail. Progressive JPG reorders data so a low-resolution preview renders before the full image downloads—useful on slow connections.
Metadata and color profiles
Both formats can embed EXIF, ICC color profiles, and XMP metadata, though many web pipelines strip metadata to save bytes. JPG EXIF often includes camera settings and GPS; PNG metadata is typically lighter. For color-critical work, embed an sRGB or Adobe RGB profile so browsers and printers interpret colors consistently.
Progressive vs baseline
Baseline JPG decodes top-to-bottom; progressive JPG interleaves frequency bands. PNG interlacing (Adam7) offers a similar progressive reveal but is rarely used on modern sites because file size increases slightly.
Security and tooling notes
Neither format executes code, but always validate uploads server-side if you accept user images. Decode limits (max dimensions, megapixel caps) prevent decompression bombs—tiny files that expand to gigabytes in memory.
Real-world size benchmarks
Consider a 12-megapixel smartphone photo (4000×3000 pixels). At quality 85, a JPG might land between 2.5 and 4 MB depending on scene complexity. The same photo saved as PNG-24 often exceeds 15 MB because every pixel is stored verbatim. Conversely, a 200×200 logo with four flat colors might be 12 KB as PNG-8 and 18 KB as JPG—the JPG introduces ringing around edges while the PNG stays razor sharp.
These patterns explain why content management systems often auto-convert uploads: WordPress and similar platforms generate JPG thumbnails for photos and preserve PNG for graphics. Understanding the underlying math helps you override defaults intelligently instead of fighting them.
Color spaces and display
Most web images use the sRGB color space. PNG and JPG can embed ICC profiles for wider gamuts like Display P3 or Adobe RGB. Without a profile, browsers assume sRGB. Mismatched profiles cause subtle color shifts—skin tones look washed out or skies turn neon. When exporting from Lightroom or Photoshop, embed sRGB unless your audience explicitly needs wide-gamut assets.
Accessibility and performance
Large images hurt Largest Contentful Paint (LCP), a Core Web Vitals metric. Serve appropriately sized JPGs for hero images—often 1600 px wide is enough for full-bleed layouts on retina displays. Pair responsive srcset attributes with modern formats. Keep PNGs for small UI assets that benefit from lossless edges; sprite sheets and icon fonts have largely given way to SVG, but PNG remains the fallback for complex icons with gradients.
Choosing quality settings in practice
JPG quality is not standardized across tools—Adobe quality 80 may differ from libjpeg quality 80. When comparing exports, judge by file size and visual inspection at 100% zoom, not by the number alone. For PNG, try lossless recompression tools before reaching for lossy alternatives; many PNGs from design tools contain uncompressed IDAT chunks that shrink 30–50% with optimization.
Free Conversion Tools
AboveTool runs conversions entirely in your browser—files never leave your device. Use these utilities when you need to switch formats without installing software:
- PNG to JPG Converter — export photographs from PNG sources with adjustable quality.
- JPG to PNG Converter — lossless re-wrap when you need a PNG container (note: this cannot restore lost JPG detail).
- JPEG Compressor — shrink JPG file size while previewing quality.
- Lossless PNG Compressor — reduce PNG size without discarding pixels.
Tip: Converting JPG → PNG does not recover information removed by lossy compression. Only convert to PNG when you need transparency or plan further lossless edits.
Related Guides
More format comparisons are on the way. For now, explore these related resources on AboveTool:
- Blog — workflow articles on images, PDFs, and developer utilities.
- Image Converters — full directory of format-to-format tools.
- Image Compressors — target-size and platform-specific optimizers.
FAQ
Is JPG the same as JPEG?
Yes. JPEG (Joint Photographic Experts Group) is the format name; JPG is simply a three-letter file extension used on older systems that limited extensions to three characters. Both refer to the same ISO/IEC 10918 standard.
Which format is better for websites?
There is no single winner. Use JPG for photos, PNG for graphics with transparency or sharp text, and modern formats like WebP or AVIF when your audience’s browsers support them. Many sites serve WebP with JPG fallbacks via the <picture> element.
Why is my PNG larger than the JPG original?
PNG is lossless. Photographic content contains noise and gradients that DEFLATE cannot compress as aggressively as JPG’s lossy algorithm. For photos, PNG files are often 5–10× larger than equivalent-quality JPGs.
Can PNG have a transparent background?
Yes. PNG supports full alpha transparency—from fully opaque to partially transparent pixels. JPG does not support transparency; transparent areas must be filled with a background color before saving.
Does converting PNG to JPG reduce quality?
Yes. JPG compression is lossy, so fine detail and transparency are discarded. Always keep a PNG master if you anticipate future edits or need to re-export at different quality levels.
What quality setting should I use for web JPG?
Start at 80% quality and compare visually. Many teams publish photos at 75–85% quality with chroma subsampling 4:2:0. Use your browser’s network panel to confirm the byte savings justify any visible change.
Are PNG and JPG supported in all browsers?
Yes—both have been universal in every major browser for decades. They remain the safest fallback formats even as WebP, AVIF, and JPEG XL gain adoption.
Which format should I use for printing?
Print workflows often prefer TIFF or high-quality PDF, but PNG works well for lossless graphics and JPG is acceptable for photo prints at high quality settings (90+). Consult your print provider’s guidelines for DPI and color profile requirements.