For photographs on the web, use WebP by default — it delivers roughly 25-35% smaller files than JPG at matching visual quality, and every current browser supports it. Keep JPG when the image has to open flawlessly in older software, email clients, print workflows or desktop apps that never added WebP support. If you are unsure, convert one photo with Universal Converter and compare the two files side by side before committing either way.
When to use WebP
WebP was built by Google specifically for the web, and for photographs it is the better default in 2024 and beyond.
- Smaller files at the same quality. A typical 1600px photo saved as WebP at quality 80 lands 25-35% lighter than the JPG equivalent. On a page with twenty photos, that is real bandwidth.
- Transparency without a second format. JPG cannot store an alpha channel at all. WebP can, so a photo with a cut-out subject no longer needs a PNG fallback that is three times the size.
- Both lossy and lossless modes. The same format handles photographic compression and pixel-perfect graphics, which means one file type across a whole site.
- Animation. WebP replaces animated GIFs with far smaller files and full color depth, no banding.
- Universal browser support. Chrome, Firefox, Safari, Edge and Opera have all supported WebP for years. The old compatibility argument is largely dead for anything rendered in a browser.
- Better quality at aggressive compression. Push both formats to a small file size and WebP holds detail longer; JPG starts showing blocking and ringing artifacts first.
If your images only ever appear inside a web page, WebP is the format to reach for.
When to use JPG
The case for JPG is not nostalgia. It is compatibility, and compatibility still matters.
- Everything opens a JPG. Word documents, PowerPoint decks, email clients, photo printing kiosks, camera software, ten-year-old phones, smart TVs, car infotainment screens. WebP support in non-browser software is patchy at best.
- Camera and scanner output. Nearly every camera and scanner writes JPG natively. Staying in JPG avoids a conversion step and a second generation of compression.
- Editing headroom. Repeatedly opening and re-saving a lossy file degrades it. JPG is the format your editing tools were designed around, and some older editors will not write WebP at all.
- Print and professional pipelines. Print shops, stock libraries and publishing systems frequently specify JPG or TIFF. Handing them WebP creates a support conversation you do not need.
- Smaller tooling footprint. No plugin, no extension, no 'why won't this open' email from a client.
- Mature, predictable tooling. Twenty years of encoders, quality scales and best-practice documentation means you know exactly what you are getting.
If the image leaves the browser — email attachment, slide deck, print, archive, handoff to someone else — JPG is the safe answer.
Why convert locally instead of on an upload site
Most 'JPG to WebP' converters work the same way: you send your file to their server, they convert it, you download the result. That is a problem for a format comparison, because you are handing over the exact photo you are trying to evaluate.
Alvseike's Universal Converter converts images between PNG, JPG, WebP, AVIF and more entirely inside your browser. Your file is opened locally, converted locally and saved locally. Nothing is transmitted, so nothing can be logged, retained, resold or leaked. For personal photos, client work, medical images or anything under NDA, that difference is the whole decision.
There are practical advantages too:
- No file-size caps. Upload sites throttle large images or charge to lift the limit. Here the ceiling is your own machine's memory.
- No watermarks and no ads. The output is your image, unchanged except for the format.
- No round trip. A 30 MB photo does not have to travel to a data center and back before you can look at it.
- Side-by-side comparison is the point. Converting both directions and comparing the two files is the only honest way to decide whether WebP's savings are worth it for your images, and doing that locally costs nothing.
If you also need to prepare the image before converting, Smart Resizer resizes to exact pixels or presets without quality loss, and Smart Cropper crops to any ratio with smart guides. Both run locally as well. For logos and icons, where a photo format is the wrong answer entirely, Image to SVG traces real vector paths instead.
One note on Alvseike's own limits, since they apply to the tools and not to your files: exports are metered at 5 runs per day without an account and 15 with a free one, and a run is one export no matter how many files it contains. Free plans process up to 3 files per batch without an account or 5 with one. There is no file-size cap on any plan. Pro is $12.99/month, removes the batch cap, adds offline use and covers all 40 Alvseike tools — images, video, audio, PDF and marketing — not just this one. See /pricing if you need unlimited daily exports.
Common mistakes
Assuming WebP always wins on size. It usually does at matched quality, but a badly encoded WebP can be larger than a well-optimized JPG. Encode quality matters more than the container. Test your actual images.
Converting a JPG to WebP and expecting a smaller file. You cannot recover data that lossy compression already discarded. Converting a JPG to WebP re-compresses an already-degraded image, and the result is often no smaller — sometimes larger. Start from the original if you have it.
Using WebP for print. Print shops want JPG, TIFF or PDF. WebP in a print workflow is a rejection email waiting to happen.
Using JPG for transparent images. JPG has no alpha channel. A transparent PNG saved as JPG gets a black or white box behind it, permanently.
Re-saving the same file repeatedly. Every lossy save throws away more detail. Convert once, from the highest-quality source, and keep the original.
Ignoring the fallback question. If you serve WebP, check whether anything downstream — a CMS, an email template, a third-party widget — needs a JPG version. Modern browsers are fine; the rest of your stack may not be.
Comparing at different quality settings. A WebP at quality 60 and a JPG at quality 90 is not a fair test. Match the visual quality, then compare file sizes.
Trusting a single test image. Savings vary by content. Smooth gradients and flat skies compress differently from detailed foliage. Run three or four of your own photos before you set a rule.