JPEG vs PNG vs HEIC vs WebP：どの画像形式を使うべき？

Choosing the wrong image format wastes storage and bandwidth. Here’s when to use JPEG, PNG, HEIC, or WebP.

The Formats at a Glance

Format	Year	Compression	Transparency	Best For
JPEG	1992	Lossy	No	Photos, web
PNG	1996	Lossless	Yes	Graphics, logos
HEIC	2017	Lossy/Lossless	Yes	iPhone photos
WebP	2010	Lossy/Lossless	Yes	Web performance

JPEG — The Universal Standard

Pros: Every device and app supports it. Decent compression.

Cons: 8-bit color only, no transparency, 30-year-old technology.

When to use: Sharing photos online, printing, any situation where compatibility is paramount. The safest choice for non-technical recipients.

PNG — For Graphics, Not Photos

Pros: Lossless compression, full transparency (alpha channel), sharp edges for text and logos.

Cons: Terrible for photos — a 12 MP photo as PNG can be 30+ MB.

When to use: Screenshots, logos, UI elements, images with text, anything requiring transparency. Never use for photographs.

HEIC — Apple’s Space Saver

Pros: Half the size of JPEG at equivalent quality, 16-bit color, transparency, stores multiple images (Live Photos, bursts) in one file.

Cons: Limited compatibility outside Apple ecosystem. Windows requires an extension.

When to use: iPhone photography (default since iOS 11). Convert to JPEG for sharing with non-Apple users using heicgo.com to preserve EXIF data.

WebP — Google’s Web Optimizer

Pros: 25-35% smaller than JPEG, supports transparency and animation, widely supported by modern browsers.

Cons: Limited support in desktop apps and older software.

When to use: Website images to improve page load speed. Most CDNs and CMS platforms auto-convert to WebP.

Size Comparison (Same 12 MP Photo)

Format	File Size	Visual Quality
PNG (lossless)	~28 MB	Perfect
JPEG (92% quality)	~4.8 MB	Excellent
WebP (92% quality)	~3.2 MB	Excellent
HEIC (equivalent)	~2.4 MB	Excellent
JPEG (80% quality)	~1.8 MB	Good

Decision Flowchart

Do you need transparency?
├─ Yes → PNG or WebP
└─ No → Is it a photo?
    ├─ Yes → HEIC (Apple devices) or JPEG (sharing/web)
    └─ No → WebP (web) or PNG (graphics)

The HEIC→JPEG Conversion Pipeline

When converting HEIC to JPEG for sharing:

1. Choose 92% quality — visually identical, half the file size of 100%
2. Preserve EXIF data — GPS and timestamps survive conversion
3. Use client-side conversion — no upload to third-party servers

heicgo.com handles all three requirements in one step.

Further Reading

• HEIC vs JPEG Comparison — the two photo formats compared
• Understanding Image File Formats — beginner’s overview
• HEIC to PNG Conversion — when to use PNG instead