PNG vs JPG vs WebP: Which Image Format Should You Use?

Most developers and designers reach for PNG or JPG by habit rather than by choice. The result is websites with images that are 3 to 5 times larger than they need to be, or product photos that look compressed and unprofessional. Understanding what each format actually does: and where each one breaks down: takes about ten minutes and saves significant headaches. This guide covers PNG vs JPG vs WebP vs AVIF, with a comparison table and practical advice for common scenarios.

JPG (JPEG): the workhorse for photographs

JPG uses a lossy compression algorithm that exploits how human vision works. It sacrifices fine detail in areas of gradual colour change (most of a photograph) while preserving sharpness at edges. The result is a small file that looks nearly identical to the original at quality settings of 75 to 85 percent. At 100 percent quality a JPG approaches lossless, but the file size grows dramatically without proportional visual benefit.

JPG is the right choice for photographs, product images, full-page hero images, and anything with a wide range of continuous tones. It is the wrong choice for logos, screenshots, text-heavy images, and anything with sharp edges against flat backgrounds: these produce visible compression artefacts (blocky areas called ringing) around high-contrast edges.

One hard limitation: JPG does not support transparency. If you need an image with a transparent background, JPG cannot do it: you will get a white or coloured fill instead. This rules it out for logos, cut-out product shots, and any UI element that needs to sit on a coloured or variable background.

PNG: lossless quality with a size cost

PNG uses lossless compression. The compressed file is mathematically identical to the original: no information is discarded. This means a PNG will always look exactly as intended, with crisp edges, solid flat colours, and no artefacts. PNG also supports full alpha-channel transparency, making it the standard choice for logos, icons, UI elements, illustrations, and screenshots.

The trade-off is file size. A PNG of a photograph will typically be 3 to 5 times larger than an equivalent JPG because lossless compression cannot reduce photographic content as aggressively as lossy compression can. Using PNG for photographs is a common and expensive mistake on websites, and it is one of the most reliably flagged issues in Lighthouse performance audits.

WebP: the modern default for most use cases

WebP was developed by Google and supports both lossy and lossless compression modes, plus transparency. In lossy mode it produces files roughly 25 to 35 percent smaller than JPG at equivalent quality. In lossless mode it beats PNG by 20 to 30 percent. It also supports animation, like GIF but with much better quality and significantly smaller files.

Browser support is now comprehensive: Chrome, Firefox, Safari 14+, and Edge all support WebP. If you are building for a modern audience, WebP should be your default format for everything. The main reason not to use it is legacy compatibility requirements (older Android browsers, Internet Explorer) or situations where you need the broadest possible file format support, such as image files intended to be opened in desktop software.

AVIF: the next step beyond WebP

AVIF is an even newer format derived from the AV1 video codec. It outperforms WebP by another 20 to 30 percent in file size at equivalent quality. Support is growing: Chrome 85+, Firefox 93+, Safari 16+: but is not yet universal. AVIF is worth adopting if you can serve it as one format in a responsive images setup with WebP or JPG as fallbacks.

Encoding AVIF is more CPU-intensive than encoding WebP or JPG. For static image pipelines where images are processed once at build time and then cached, this extra encoding cost is invisible to users. For dynamic pipelines handling user-uploaded images in real time, the encoding overhead is worth measuring before committing to AVIF universally. In practice, most modern image CDNs support on-demand AVIF conversion, making the encoding cost a server-side concern rather than a user-facing one.

PNG vs JPG vs WebP vs AVIF: format comparison

The four formats cover different trade-offs across compression, compatibility, and capability. Here is a side-by-side comparison of the properties that matter most for web use:

One pattern to note: JPG and PNG have universal support and remain the safe fallback choice. WebP and AVIF offer meaningfully better compression but require fallbacks for full compatibility. For most new projects targeting modern browsers, defaulting to WebP covers all scenarios with zero compatibility risk.

How your image format choice affects page speed and SEO

Images are typically the heaviest assets on any web page. According to HTTP Archive data, images account for over 40 percent of the average page weight. The format you choose directly determines how much data the browser needs to download. A typical product photograph at 1,200 pixels wide might be 900 KB as a PNG, 130 KB as a JPG at 80 percent quality, 95 KB as a WebP, and 70 KB as an AVIF. On a page with ten product images, switching from PNG to WebP alone saves roughly 8 MB per page load.

Google's Core Web Vitals include Largest Contentful Paint (LCP), which measures how quickly the largest visible element loads. Hero images, product photographs, and featured images are almost always the LCP element on a page. Serving them in WebP or AVIF rather than PNG or JPG is one of the highest-impact single changes you can make to improve LCP scores. Google's PageSpeed Insights and Lighthouse audits both flag oversized PNG and JPG files as conversion opportunities when a smaller format would produce a significantly smaller file.

Choosing the right quality setting for lossy formats

For formats that support lossy compression (JPG, WebP lossy, AVIF), quality is a dial between file size and visible detail. The relationship is not linear: dropping from 100 percent to 80 percent typically reduces file size by 60 to 70 percent with almost no visible change. Dropping from 80 to 60 percent removes another 30 to 40 percent of size with increasing but often still acceptable quality loss. Below 60 percent, artefacts become distracting on most images, particularly around text, sharp edges, and faces.

A practical starting point: use 80 to 85 for photographs where fine detail matters (product close-ups, editorial images, portfolio shots), 70 to 75 for background images and decorative elements where slight softness is unnoticeable, and 60 to 65 for thumbnails displaying below 200 pixels wide. Always check the output at 100 percent zoom before publishing: artefacts that are invisible at thumbnail scale can be obvious on a large display.

• •JPG: start at 85, reduce until artefacts appear near edges or smooth gradients, then step back one notch
• •WebP lossy: roughly equivalent to JPG at 5 to 10 points lower (WebP 75 is approximately JPG 80 in visual quality)
• •AVIF: quality scales differently from JPG or WebP, start at 65 to 70 and compare against the source carefully
• •PNG and WebP lossless: no quality setting applies, all lossless output is bit-identical to the source image

Responsive images: serving the right format to every browser

The HTML picture element lets you offer multiple formats and let the browser automatically pick the best one it supports. A standard responsive image setup offers AVIF first, WebP as a fallback, and JPG as a final fallback for older browsers. Modern Chrome users get the smallest AVIF file, slightly older browsers get WebP, and only legacy environments receive JPG. No JavaScript is needed: the browser handles the selection based on its own declared format support.

The srcset attribute handles a related concern: serving different image sizes at different viewport widths, so mobile users do not download a 1,800-pixel image to display at 400 pixels. Format negotiation via picture and size negotiation via srcset are complementary. In Next.js, the built-in Image component handles both automatically: wrapping an img in Image means Next.js serves the right format and the right size with no extra configuration.

PNG vs JPG vs WebP in real projects

For blog and editorial sites with article photographs, WebP covers all photographic content and PNG handles diagrams, screenshots, and images with text overlay. If your CMS or hosting supports AVIF delivery, use it with WebP as a fallback. The quality difference between carefully compressed WebP and the originals is invisible to readers, while the page speed difference is real and measurable.

For e-commerce product catalogues, WebP for product photographs is now standard practice. If your product images have transparent backgrounds, WebP with transparency replaces both PNG (for cut-out shots) and JPG (for white-background shots) in a single format. At catalogue scale the savings compound: a catalogue of 5,000 product images at 100 KB smaller per image saves 500 MB of total data per full catalogue crawl.

For logos and brand assets used in UI, SVG is usually a better choice than any raster format. SVG scales to any size without quality loss and produces smaller files than PNG for simple vector graphics. Reserve PNG for complex logos with photographic elements or many colours where SVG would be impractically verbose. For favicons, use PNG at 32x32 and 192x192 as a baseline, and serve an ICO file for the broadest legacy browser support.

Common mistakes when choosing image formats

Most image format errors follow a small set of repeating patterns. Knowing them in advance avoids the most costly ones.

• •Saving photographs as PNG: produces files 3 to 5 times larger than equivalent JPG or WebP with no visible quality benefit for photographic content
• •Saving logos or icons as JPG: lossy compression introduces artefacts around sharp edges and flat colours, which are especially visible in logos and UI elements
• •Converting a JPG to PNG to improve quality: the quality loss from the original JPG compression is baked in permanently. Converting to lossless PNG makes the file larger without recovering any lost detail
• •Using WebP without a fallback in shared files: if users will download and reshare the images, some applications still do not open WebP natively. For download-intended files, JPG or PNG is safer
• •Skipping format conversion in the production pipeline: frameworks and CDNs can automate this. If you are serving raw PNGs and JPGs without a conversion step, you are likely missing easy performance gains

A simple decision tree

• •Photograph or image with continuous tones, no transparency: WebP (first choice), JPG (fallback)
• •Logo, icon, screenshot, illustration with flat colours: WebP lossless or PNG
• •Image needs to be transparent: WebP, PNG, or AVIF (never JPG)
• •Maximum browser compatibility required: JPG or PNG
• •Highest possible compression with modern browser: AVIF with WebP fallback
• •Animated image: WebP or AVIF (much better quality and smaller files than GIF)

File size in practice

To give a sense of scale: a typical product photograph at 1,200 by 800 pixels might be 800 KB as a high-quality PNG, 120 KB as a JPG at 80 percent quality, 85 KB as a WebP at equivalent quality, and 65 KB as an AVIF. On a page with 10 product images, the difference between PNG and WebP is roughly 7 MB of data, which translates directly to load time on mobile connections. Multiply that across an entire site and the format choice becomes one of the highest-leverage performance decisions you can make.

How to convert between image formats

Format conversion works best from the highest-quality source file available. The typical workflow: start with a large PNG or uncompressed source, convert once to the target format at the target dimensions, and use the converted files in production. Never re-convert from a lossy output: converting a JPG to WebP applies lossy compression twice and compounds quality degradation. What looks fine on the first conversion often shows clear artefacts after a second round of lossy encoding.

For batch conversion of many images at once, the Image Format Converter handles multiple files simultaneously. Drop in your source images, select the output format (JPG, PNG, WebP, or AVIF) and quality level, and download all the results as a ZIP. The conversion runs entirely in your browser, so none of your images are uploaded to a server.