Why the format you choose matters more than you think
The difference between a well-chosen and a poorly-chosen image format isn’t academic. A JPG version of a logo looks blurry and compressed. A PNG version of a high-resolution photograph bloats a page by 3–5× and kills load time. A HEIC photo sent to a Windows user opens a blank icon.
These aren’t edge cases — they’re daily frustrations for anyone who works with images. This guide cuts through the noise: what each format actually does, where it wins, and where it fails.
The 6 formats you need to know
JPG vs PNG — the decision most people get wrong
This is the most common choice and the most commonly botched one. The rule is simple:
- Photograph?JPG. Lossy compression is invisible in photos — the human eye doesn’t notice 5% quality loss in a sunset or a portrait. JPGs of typical web photos run 50–200KB. PNG versions of the same image run 500KB–2MB.
- Screenshot, logo, graphic with text? PNG. Lossy compression destroys sharp edges and makes text look fuzzy. The extra file size is worth it. If you ever see a logo or diagram that looks slightly blurry with coloured smears around edges — someone saved it as a JPG.
Need to switch? Convert JPG to PNG or convert PNG to JPG in your browser — no upload, no account.
Why WebP should be your default for the web
WebP was created by Google in 2010 and is now supported by every major browser. It offers:
- 25–35% smaller file sizes than JPG at equivalent visual quality
- Lossless compression (like PNG) for graphics — typically 25% smaller than PNG
- Full alpha channel transparency
- Animation support (like GIF, but far smaller)
If you’re building a website in 2026, there is almost no reason to serve JPGs or PNGs instead of WebP equivalents. The only exception is email clients, which still have inconsistent WebP support — use JPG for anything going into email.
Convert your images: WebP to JPG · JPG to WebP · PNG to WebP
AVIF: the next generation (worth the switch?)
AVIF (AV1 Image File Format) is the newest major image format and produces strikingly small files. A typical photograph that weighs 200KB as a JPG and 150KB as a WebP often weighs 80–100KB as an AVIF with no visible quality difference.
The tradeoffs:
- Encoding is slow— AVIF takes significantly longer to compress than JPG or WebP. For bulk batch conversion this matters. For one-off conversions it’s a 2–3 second difference.
- Browser support— All major browsers support AVIF as of 2024 (Chrome 85+, Firefox 93+, Safari 16+, Edge 121+). If you’re targeting modern users, AVIF is safe.
For high-traffic e-commerce sites or content-heavy publications, AVIF can meaningfully reduce bandwidth costs and improve Core Web Vitals scores. For a personal project or low-traffic site, the difference is negligible — stick with WebP.
Convert to AVIF: AVIF to JPG · AVIF to PNG
HEIC: the iPhone problem
Since iOS 11, iPhones default to HEIC (High Efficiency Image Container) for photos. It’s a smart default for Apple users — HEIC files are roughly half the size of equivalent JPGs, and iOS handles them natively. The problem starts when you share them.
Windows does not open HEIC files by default. Most social media platforms, content management systems, and image editors don’t accept them. If you’ve ever attached a photo from your iPhone to an email and the recipient got a blank icon, HEIC is why.
The practical workflow: before sharing iPhone photos with anyone on Windows, or before uploading to a website, convert to JPG. Convert HEIC to JPG or HEIC to PNG — done in your browser, no app needed.
File size in practice: a real comparison
Same photograph (1920×1280 px, typical travel photo), exported in different formats:
When to use SVG
SVG is fundamentally different from every other format on this list. While JPG, PNG, WebP, and AVIF store images as grids of pixels, SVG stores shapes as mathematical instructions — lines, curves, fills. This means SVG:
- Scales to any resolution without quality loss (retina-perfect at any size)
- Can be styled with CSS and animated with JavaScript
- Is often 2–10KB for simple graphics that would be 50KB+ as PNG
Use SVG for logos, icons, charts, maps, and any illustration that isn’t photographic. Never use SVG for photographs — SVG is not designed for photographic data and the file size would be enormous.
The fast answer by use case
Convert any image format — free, in your browser
FormatDrop runs entirely in your browser. Your files never leave your device.
What is the best image format for the web?↓
WebP is the best general-purpose format for websites today — smaller than JPG and PNG with equivalent or better quality, and supported by all modern browsers. AVIF is even smaller but slower to encode and has slightly lower browser support. For photos: WebP or AVIF. For logos with transparency: WebP or PNG. For legacy compatibility: JPG.
What is the difference between JPG and PNG?↓
JPG uses lossy compression — it discards some image data to reduce file size, which makes it ideal for photographs where small quality loss is invisible. PNG uses lossless compression — every pixel is preserved exactly, making it ideal for graphics, screenshots, logos, and anything with text or sharp edges. PNG also supports transparency; JPG does not.
Should I use WebP or AVIF?↓
AVIF files are typically 20–50% smaller than WebP at similar quality, but AVIF encoding is slower and browser support is slightly lower (though all major browsers support it as of 2024). For new projects prioritising performance, AVIF is the better choice. For maximum compatibility with minimal setup, WebP is the safer default.
What is HEIC and can I open it on Windows?↓
HEIC (High Efficiency Image Container) is Apple's default photo format on iPhone and iPad since iOS 11. It produces files about 50% smaller than JPG at similar quality. Windows does not natively open HEIC files in most configurations — you need to install a codec or convert the file to JPG or PNG first. FormatDrop converts HEIC to JPG or PNG entirely in your browser.
When should I use SVG instead of PNG or JPG?↓
SVG is a vector format — it stores shapes as mathematical instructions rather than pixels, so it scales to any size without quality loss. Use SVG for logos, icons, illustrations, and any graphic that needs to look sharp at all sizes. SVG is not suitable for photographs.