Lossy or lossless: which compression should I use for web images?

Use lossy (JPG, WebP, AVIF) for photographs — the human eye barely notices the difference at quality 80–85, and file sizes are 5–20× smaller. Use lossless (PNG, WebP-lossless) for screenshots, UI mockups, logos and anything with sharp edges or text — lossy creates ugly artifacts around boundaries.

When should I prefer WebP or AVIF over JPG/PNG?

For new projects in 2026, WebP is supported by all modern browsers (95%+ of traffic) and saves 25–35% over JPG at the same visual quality. AVIF is even more efficient (40–50% smaller) but encoding is slower and Safari support is recent. Use WebP as the default and AVIF as the progressive enhancement via <picture> with JPG fallback.

Does conversion preserve EXIF metadata (camera, GPS, date)?

It depends on the tool: ImageMagick and FFmpeg copy EXIF by default, while cwebp drops it unless you pass -metadata all . KaijuConverter strips metadata server-side after conversion to protect your privacy — if you need to keep camera or GPS data, use a desktop tool you control.

Why does my converted image look slightly different from the original?

Three common causes: (1) ICC color profiles dropped during conversion shift colors slightly; (2) chroma subsampling (4:2:0) reduces color accuracy in lossy JPG/WebP; (3) the new format may not support all features of the original (e.g. PNG → JPG drops transparency to white). For pixel-perfect results stick to lossless formats and preserve color profiles explicitly.

Lossy or lossless: which compression should I use for web images?

Use lossy (JPG, WebP, AVIF) for photographs — the human eye barely notices the difference at quality 80–85, and file sizes are 5–20× smaller. Use lossless (PNG, WebP-lossless) for screenshots, UI mockups, logos and anything with sharp edges or text — lossy creates ugly artifacts around boundaries.

When should I prefer WebP or AVIF over JPG/PNG?

For new projects in 2026, WebP is supported by all modern browsers (95%+ of traffic) and saves 25–35% over JPG at the same visual quality. AVIF is even more efficient (40–50% smaller) but encoding is slower and Safari support is recent. Use WebP as the default and AVIF as the progressive enhancement via <picture> with JPG fallback.

Does conversion preserve EXIF metadata (camera, GPS, date)?

It depends on the tool: ImageMagick and FFmpeg copy EXIF by default, while cwebp drops it unless you pass -metadata all . KaijuConverter strips metadata server-side after conversion to protect your privacy — if you need to keep camera or GPS data, use a desktop tool you control.

Why does my converted image look slightly different from the original?

Three common causes: (1) ICC color profiles dropped during conversion shift colors slightly; (2) chroma subsampling (4:2:0) reduces color accuracy in lossy JPG/WebP; (3) the new format may not support all features of the original (e.g. PNG → JPG drops transparency to white). For pixel-perfect results stick to lossless formats and preserve color profiles explicitly.

DNG Format Guide: Adobe's Universal RAW Standard Exp

What Is DNG?

DNG (Digital Negative) is an open, royalty-free RAW file format developed by Adobe in 2004. Its goal: create a universal standard for camera RAW files, unlike proprietary formats from each manufacturer — CR2/CR3 (Canon), NEF (Nikon), ARW (Sony), RAF (Fujifilm), ORF (Olympus).

DNG vs Proprietary RAW

Feature	Proprietary RAW	DNG
Open standard	❌	✅
File size	Varies	15–20% smaller
XMP metadata	Separate .xmp file	✅ Embedded
Long-term compatibility	Manufacturer-dependent	✅ Guaranteed

DNG Compression Types

Lossless DNG: completely preserves original RAW data.
Lossy DNG: reduces file size ~75% — visually indistinguishable for most uses.
Linear DNG: demosaiced sensor data, more compatible but larger.
32-bit HDR DNG: generated by Lightroom when merging HDR exposures.

Cameras That Use DNG Natively

Leica (M, Q, SL, CL), Pentax, Hasselblad, Sigma (Foveon), various DJI drones.

Converting RAW to DNG

Adobe DNG Converter (free)

Download Adobe DNG Converter from adobe.com.
Drag in folders with your RAW files.
Choose DNG type (lossless for archival).
Convert.

From Lightroom

Library → Photo → Convert to DNG...

ExifTool (command line)

# View all DNG metadata
exiftool photo.dng

Should You Convert to DNG?

Reasons to convert: smaller files, embedded metadata, better long-term compatibility.

Reasons to keep proprietary RAW: Capture One prefers proprietary; manufacturer software (Canon DPP, Nikon ViewNX) works best with native RAW.

Recommendation: keep original RAW; convert to DNG for your active Lightroom workflow.

Conclusion

DNG is Adobe's bet on unifying fragmented RAW formats. For Lightroom-centric workflows, DNG offers clear advantages. For Capture One or manufacturer software users, proprietary RAW remains the practical choice.

Advanced Use Cases

Web optimization at scale: e-commerce sites with thousands of products can reduce bandwidth costs 60-80% by migrating from JPG to AVIF or WebP. Cloudflare Images, Imgix and Cloudinary offer on-the-fly transformation based on client Accept header — serving AVIF to modern Chrome/Edge, WebP to Safari/Firefox, JPG fallback to legacy browsers. Print-ready output: converting RGB to CMYK with ICC profile (US Web Coated SWOP v2 for commercial offset, FOGRA39 for European) ensures printed colors match preview on calibrated screen. PDF/X-1a and X-4 are formats required by professional printers. Professional photography: Adobe workflow consists of RAW (camera input) → DNG (archival) → PSD (non-destructive editing) → TIFF (deliverable) → JPG/WebP (web/social). Each stage preserves different capabilities. Vector graphics: SVG is preferred for logos, icons, flat illustrations — scales infinitely without loss and animates with CSS/JavaScript. For modern UIs, icon fonts (Font Awesome) are being replaced by SVG sprites for better accessibility and customization.

Best Practices and Professional Tips

Format selection by content: photographs → JPG (quality 85-95) or WebP (quality 80-90); graphics with text/fine lines → PNG or WebP lossless; flat illustrations → SVG; UI icons → SVG; screenshots → PNG; HDR → AVIF or JPEG XL. Color profile management: always embed ICC profile in professional files (Adobe RGB for pre-press photography, sRGB for web, Display P3 for Apple ecosystem). Without embedded profile, viewers assume sRGB which can cause visible color shifts. Resolution vs size: for web display, 72 DPI is sufficient; for professional print, 300 DPI minimum. Lazy loading + responsive images: combine <img loading="lazy" srcset> with AVIF/WebP fallback chain for bandwidth savings without sacrificing UX. Metadata privacy: smartphone JPG files contain GPS, camera model, exact date — use exiftool -all= to strip before uploading to social networks if privacy matters.

Compatibility and Technical Considerations

KaijuConverter supports more than 30 image formats (JPG, PNG, WebP, AVIF, HEIC/HEIF, GIF, BMP, TIFF, SVG, ICO, PSD, RAW from multiple vendors, JPEG XL) using ImageMagick 7.x, libvips, and format-specific libraries (libpng, libjpeg-turbo, libwebp, libavif, librsvg). We process images up to 100 MB with resolutions up to 16384×16384 pixels and depths of 8/10/12/16-bit per channel. EXIF and metadata: we read all embedded information (camera, lens, GPS, capture data, ICC profile) and migrate it to output when destination format supports it — critical for professional workflows that depend on provenance tracking. HDR: we support PQ and HLG transfer functions for AVIF/JPEG XL/HEIC HDR (rec.2020 color space). Performance: a typical 5 MB JPG→WebP conversion takes 1-3 seconds; iPhone 12 Mpix HEIC→JPG takes 2-5 seconds; multi-layer PSD→PNG flat may require 5-15 seconds depending on complexity. Privacy: TLS 1.3 encryption, isolated Docker containers, automatic deletion after 2 hours with multi-pass overwrite.

Related conversions

Most teams that read this guide convert images in one of these directions:

DNG Format Guide: Adobe's Universal RAW Standard Explained