Comparison

JPG vs PNG: When to Use Lossy vs Lossless Images for Web, Screenshots, and Photography

Q: Why is my JPG file size large but the image looks blurry?

You've likely set a high quality (e.g., 95) on a low-resolution image. The file is large because the compression is minimal, but the blur comes from the low source resolution. Compress at quality 70-80 and serve at the display resolution (max 1200 px wide). Resizing before compression saves far more bytes than tweaking quality alone.

JPG (JPEG) and PNG are the two most common image formats on the web, but they are not interchangeable. JPG is a lossy format designed for photographs — it compresses aggressively by discarding visual detail the human eye won't notice. PNG is a lossless format designed for graphics — it compresses without any quality loss and supports transparency. Choosing wrong means either a 300 KB photo where 80 KB would do, or a pixelated logo with artifact rings.

TL;DR

	JPG	PNG
Compression	Lossy — discards data (quality slider)	Lossless — retains all data
Transparency	No alpha channel	Full 8-bit alpha transparency per pixel
Best for	Photos, paintings, gradients	Logos, icons, screenshots, text-heavy images
Photo size (same quality)	~80 KB (q80)	~300 KB
Quality at q80	Indistinguishable from original on screen	Identical to original (lossless)

The options in depth

JPG

The photographic workhorse — ~4× smaller than PNG for photos.

JPG's compression algorithm (DCT — Discrete Cosine Transform) splits the image into 8×8 pixel blocks, converts them to frequency components, and discards high-frequency information (sharp edges, fine texture) that human vision is less sensitive to. At quality 80, the compression is visually lossless for photos but unacceptable for screenshots (text becomes blurry). At quality 40, visible compression artifacts (blocky squares in smooth gradients) appear.

Good for

·Photographs and digital paintings
·Any image where 4× file-size savings matters
·Serving to mobile users on metered data connections

Avoid when

·Logos and icons (visibility of artifact blocks)
·Images containing text (text becomes unreadable)
·Images needing transparency

Try it: PNG to JPG Converter →

PNG

The lossless format — pixel-perfect for logos, icons, and screenshots.

PNG uses DEFLATE compression (same as ZIP), which reduces file size by eliminating redundancy without losing any data. A PNG screenshot is byte-for-byte identical to the source pixel grid. PNG's key advantage over JPG for graphics is the absence of compression artifacts around sharp edges — a red logo on a white background will have crisp boundaries, not the fuzzy halo that JPG creates.

Good for

·Screenshots (exact pixel representation)
·Logos and icons with sharp edges
·Any image requiring transparency (alpha channel)
·Images with text (text stays sharp)

Avoid when

·Photos (JPG or WebP at 4× smaller)
·Web where every KB counts (WebP for graphics is even smaller)

Try it: JPG to PNG Converter →

Which one should you pick?

→ Should I export screenshots as JPG or PNG?

PNG — always. Screenshots contain text, UI elements, and sharp edges. JPG compression creates visible artifacts around text and lines that make the screenshot look unprofessional. The 300 KB vs 80 KB file-size penalty is worth the quality.

→ Should I use JPG or PNG for my blog's hero images?

JPG at quality 80 — photos benefit from JPG compression without visible loss, and the 4× smaller file improves page load time (Core Web Vitals / LCP). If you need transparency, switch to WebP — it supports both lossy (like JPG) and lossless (like PNG) + alpha.

Common pitfalls

⚠Re-saving a JPG file repeatedly (edit → save → edit → save) compounds compression artifacts. Each re-save applies the lossy compression again on already-compressed data. Always keep a lossless master in PNG or RAW and export JPEGs from it.
⚠PNG-8 (indexed color, max 256 colors) is a different format from PNG-24 (true color + alpha). Many tools default to PNG-24, but if your image uses < 256 distinct colors, PNG-8 produces identical quality at a fraction of the file size.

Frequently Asked Questions

Why is my JPG file size large but the image looks blurry?

You've likely set a high quality (e.g., 95) on a low-resolution image. The file is large because the compression is minimal, but the blur comes from the low source resolution. Compress at quality 70-80 and serve at the display resolution (max 1200 px wide). Resizing before compression saves far more bytes than tweaking quality alone.

Related comparisons

WebP vs AVIF

WebP and AVIF both replace JPG and PNG with dramatically smaller file sizes. WebP has universal browser support; AVIF is 20-30% smaller but only supported in modern browsers. This guide picks the right format for every deployment.

SVG vs PNG

SVG is resolution-independent and code-editable; PNG is pixel-perfect and universally supported. This guide picks the right format for icons, logos, screenshots, and illustrations.