Image Format Converter

Picking an image format isn't just a technical choice — it's a quality, file-size, and compatibility decision rolled into one. The wrong choice can quadruple your page weight or lose all your alpha transparency. Most photographers default to JPG out of habit. Most designers default to PNG because they remember it being "the high-quality one". Both defaults are now usually wrong — WebP has been a strict upgrade over both for most use cases since 2018, and AVIF is starting to take over from WebP for the most demanding compression jobs.

JPG (.jpg / .jpeg)

The 1992 standard. Lossy compression, no alpha channel, 8-bit colour, maximum compatibility. Use JPG for photographs going to platforms where you don't control the consumer (email attachments, photo print services, legacy CMS systems). Default quality of 85 is the sweet spot — drop below 70 and compression artefacts become visible; push above 90 and file size balloons without visible improvement. JPG is the wrong choice for screenshots, line art, logos, or anything with sharp text — the DCT-based compression smears edges and creates "mosquito noise" around contrast boundaries.

PNG (.png)

The lossless alpha-supporting format from 1996. Use PNG when you need transparency (logos with no background), pixel-perfect screenshots, line art, or anything where lossy compression would visibly degrade quality. PNG files are typically 3-10× larger than the equivalent JPG, so don't reach for it for photographs. PNG-8 (256-colour indexed) can produce tiny files for simple graphics; PNG-24 supports full 16M colours plus alpha.

WebP at quality 80 is typically 25-35% smaller than JPG at quality 85 with no visible difference. AVIF at quality 70 is typically another 20-30% smaller than that.

WebP (.webp)

Google's 2010 format, finally a safe universal default in 2020 when Safari added support. WebP supports both lossy (like JPG) and lossless (like PNG) modes, plus alpha transparency in both — something JPG never had. For photographs, lossy WebP at quality 80 looks the same as JPG at quality 85 but produces files 25-35% smaller. For screenshots, lossless WebP is typically 25-50% smaller than PNG with identical visual output. Browser support: Chrome, Firefox, Edge since launch; Safari 14+ (macOS Big Sur); IE never. If you can drop IE, drop JPG and PNG too.

AVIF (.avif)

The 2019 format derived from the AV1 video codec. Best-in-class compression — typically 50% smaller than JPG at the same visible quality, 20-30% smaller than WebP. Supports up to 12-bit colour depth (matters for HDR), wide colour gamut, alpha. The catch: encoding is slow (it can be 10-50× slower than JPG to compress), browser decode support is now universal but encoding still varies. Use AVIF for hero images and product photos where the bandwidth saving matters; stick with WebP for thumbnails and smaller images where the marginal saving isn't worth the slower encode.

HEIC (.heic / .heif)

Apple's default photo format since iOS 11. Roughly comparable to AVIF in compression efficiency. Decoded natively in Safari and Photos, increasingly accepted on Windows and Android. Browsers cannot encode HEIC at all (Apple keeps it proprietary on the encode side). Useful as an input format — your iPhone takes HEIC photos and this tool will convert them to JPG/WebP/AVIF for the web.

The APAC mobile reality

Image format choice matters more in APAC than anywhere else because of bandwidth diversity. Singapore, Hong Kong, Japan, South Korea, Taiwan have residential fibre averaging 200 Mbps to 1 Gbps — a 2 MB hero image loads in milliseconds. Malaysia, Thailand, Vietnam, Philippines, Indonesia have median mobile connections of 20-50 Mbps with significant rural variation — that same 2 MB image takes 1-3 seconds on a typical phone. India is split: tier-1 cities have fast 4G/5G, but a meaningful share of users are still on 2G/3G fallback during peak hours. China's mobile network is fast, but data caps are tight (most plans cap at 30-100 GB/month). Net result: serving WebP or AVIF instead of JPG is the single biggest performance win you can make for APAC audiences, and it's invisible to users — only their data bill notices. Major APAC sites (Lazada, Shopee, Bukalapak, Tokopedia, Naver, Mercari) all serve WebP by default with JPG fallback via the <picture> element.