Is WebP always better than JPEG and PNG?

For web use, WebP is usually the best choice — it produces smaller files than both JPEG and PNG at comparable quality, and it supports both lossy and lossless compression plus transparency. However, WebP has weaker support in some contexts: older email clients may not display it, some print workflows require JPEG or TIFF, and certain legacy software cannot open WebP files. For maximum compatibility outside the web, JPEG (photos) and PNG (graphics) remain safer choices.

Why do PNGs produce much larger files than JPEGs?

PNG uses lossless compression — it preserves every pixel exactly, which means the file must store all original data. JPEG uses lossy compression, which discards visual information the human eye is unlikely to notice. For photographs with millions of subtle color variations, this difference is dramatic: a 4000x3000 photo might be 2MB as JPEG but 15MB as PNG. For simple graphics with flat colors and few unique values, PNG compression is quite efficient and the size gap narrows considerably.

Does converting JPEG to PNG improve image quality?

No. Converting JPEG to PNG preserves the current state of the image losslessly — including all JPEG compression artifacts already present. The artifacts are baked into the pixel data. Going from JPEG to PNG just prevents further quality loss on subsequent saves, but it cannot recover detail that was already discarded during JPEG compression. The file will be larger (PNG stores data losslessly) without looking any better.

What format should I use for images with transparent backgrounds?

PNG or WebP — both support full alpha-channel transparency. JPEG does not support transparency at all. Between PNG and WebP, WebP produces smaller files (typically 25-35% smaller) with identical visual quality. Use WebP for web content where browser support is guaranteed. Use PNG when sharing files that might be opened in older software, email clients, or print workflows where WebP support is uncertain.

JPEG vs PNG vs WebP — When to Use Each Format

Every time you save an image, you're making a choice about quality, file size, and compatibility — whether you realize it or not. JPEG, PNG, and WebP each handle that trade-off differently, and picking the wrong format means either bloated files that slow down your website or visible artifacts that make your images look cheap. The difference between a 200KB JPEG and a 4MB PNG of the same photo is real, and so is the quality gap between a well-compressed WebP and an over-compressed JPEG. Scanly's Format Converter lets you switch between all three formats instantly in your browser. Try it free →

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JPEG — Built for Photographs

JPEG has been the default photo format since 1992. It uses lossy compression — it analyzes the image, identifies visual information that humans are unlikely to notice, and discards it. The result is dramatically smaller files. A 24-megapixel photo that would be 70MB uncompressed becomes 3-5MB as a JPEG at high quality, with no visible difference to most viewers.

The compression works by dividing the image into 8×8 pixel blocks and converting each block into frequency components using a mathematical transform (DCT). High-frequency details — subtle textures, fine gradients — are reduced or removed. At high quality settings (85-95%), the loss is invisible. At low quality (below 60%), you start seeing the characteristic JPEG artifacts: blocky patterns around sharp edges, color banding in gradients, and smeared fine details.

JPEG's weakness is that every save recompresses the image. Open a JPEG, make a small crop, save it — quality drops. Do that five times and the artifacts become obvious. This is called generation loss, and it's why photographers shoot in RAW and only export to JPEG as a final step. Use the Quality Analyzer to check how much compression damage an image has already accumulated.

Use JPEG for: photographs, camera output, images with complex color gradients, any situation where file size matters more than pixel-perfect accuracy. Most photos you see on the web are JPEGs for good reason.

Don't use JPEG for: logos, text, screenshots, line art, anything with sharp edges and flat colors (artifacts will be visible), or anything requiring transparency.

PNG — Pixel-Perfect, No Compromises

PNG uses lossless compression. Every pixel in the original is preserved exactly — open a PNG, save it again, and the file is bit-for-bit identical. No generation loss, no artifacts, no quality degradation regardless of how many times you edit and resave.

The trade-off is file size. PNG compresses data by finding patterns — runs of identical pixels, repeating sequences — but it can't discard information. A photograph with millions of unique color values compresses poorly because there are few patterns to exploit. That same 24-megapixel photo that's 4MB as JPEG might be 30MB as PNG. For simple graphics — a logo with four colors, a chart with flat backgrounds — PNG compression is excellent and file sizes are reasonable.

PNG also supports transparency through an alpha channel. Each pixel can have a value from fully opaque to fully transparent, enabling smooth edges against any background. This is why every logo, icon, and UI element with a transparent background is distributed as a PNG. JPEG has no transparency support at all.

Use PNG for: logos, icons, screenshots, diagrams, text-heavy images, anything with transparency, anything requiring pixel-perfect accuracy, source files for further editing.

Don't use PNG for: photographs on the web (file sizes are impractical), large images where some quality loss is acceptable, or any context with bandwidth constraints.

WebP — The Modern Compromise

Google developed WebP specifically to replace both JPEG and PNG on the web. It supports lossy compression (like JPEG), lossless compression (like PNG), and transparency (like PNG) — all in one format. At comparable visual quality, WebP files are typically 25-35% smaller than JPEG and significantly smaller than PNG.

The lossy mode produces cleaner results than JPEG at equivalent file sizes. Where JPEG shows blocky 8×8 artifacts, WebP's block-based compression uses variable block sizes and better prediction algorithms, producing smoother gradients and fewer visible artifacts at the same file size. Lossless WebP outperforms PNG on compression efficiency for most image types.

The trade-off is compatibility. Every modern browser supports WebP — Chrome, Firefox, Safari, Edge. But older software, some email clients, and certain print workflows don't. If you're preparing images for a website you control, WebP is almost always the right choice. If you're sending images via email or sharing files that might be opened in unknown software, JPEG and PNG are safer bets.

Use WebP for: web content where you control the platform, any image that needs the smallest possible file size, images requiring both quality and transparency.

Don't use WebP for: email attachments (some clients won't display them), print workflows, legacy system compatibility, or when the recipient's software support is unknown.

Quick Decision Guide

The choice comes down to three questions. Is it a photograph or a graphic? Do you need transparency? Where will it be used?

Photographs for the web: WebP (lossy) first choice, JPEG second. Photographs for sharing or print: JPEG. Screenshots, logos, diagrams: WebP (lossless) if staying on the web, PNG if sharing externally. Anything with transparency: WebP or PNG, never JPEG. Source files for editing: PNG (lossless preserves all data for future edits).

If you're unsure, the Format Converter lets you convert between all three formats and compare file sizes and quality side by side. Export the same image in all three formats, check the file sizes, zoom in on detailed areas, and decide which trade-off makes sense for your use case. For a walkthrough of the conversion itself, see our step-by-step format conversion guide.

Compression Quality — Finding the Sweet Spot

For JPEG and lossy WebP, the quality setting determines the trade-off between file size and visual fidelity. The relationship isn't linear — the biggest quality loss happens at the lower end of the scale.

Quality 95-100%: visually indistinguishable from the original, but file sizes are only 10-15% smaller than lossless. Rarely worth it — you're paying for invisible perfection. Quality 80-90%: the sweet spot for most photos. Files are 5-10x smaller than lossless with no visible artifacts at normal viewing sizes. Quality 60-75%: visible artifacts on close inspection, but acceptable for thumbnails, previews, and low-bandwidth situations. Below 60%: noticeable degradation. Only use this if extreme file size constraints demand it.

Use the Image Compressor to experiment with quality levels and see the exact file size impact. Compress at quality 85, then at 75 — if you can't see the difference, save the bandwidth.

AVIF, HEIC, and What's Coming Next

AVIF is the newest contender — based on the AV1 video codec, it achieves 20-30% better compression than WebP at equivalent quality. Browser support is growing but not universal yet. HEIC is Apple's format for iPhone photos — excellent compression but limited support outside Apple's ecosystem, which is why converting HEIC to JPG is a common first step before sharing. Neither has reached the ubiquity of JPEG, PNG, or WebP.

For now, WebP is the practical modern choice. It has near-universal browser support, outperforms JPEG and PNG, and handles both photos and graphics well. AVIF will likely become the standard in a few years, but today WebP hits the best balance of quality, size, and compatibility.

Need to convert between any of these formats? The Format Converter handles JPEG, PNG, WebP, AVIF, BMP, GIF, and ICO — all processing happens in your browser, no uploads required.