Which image format is best for website photos?

Start by comparing AVIF and WebP for modern web delivery, then keep JPEG as a compatibility fallback. The smallest format depends on the image, encoder, quality target, and browser delivery path, so test representative photos rather than applying one quality number to every asset.

Is WebP better than JPEG?

For many web photos, WebP can reach similar visual quality with fewer bytes. JPEG still has the widest compatibility across older software, email clients, upload forms, and document workflows. Use WebP with a JPEG fallback when the destination allows it.

Is AVIF better than WebP?

AVIF often compresses photographic images more efficiently, while WebP is usually simpler and cheaper to encode. The practical choice depends on decode behavior, build or CDN support, and the clients you need to serve.

Should screenshots use PNG or WebP?

Use PNG or lossless WebP when text, thin lines, and exact pixels matter. Lossy JPEG, WebP, or AVIF can create halos, ringing, or color shifts around interface text. Compare the export at 100% before publishing.

Which format supports transparency?

PNG, WebP, and AVIF can carry transparency. PNG is the safest universal and editing format; lossless WebP is often a smaller web delivery copy; AVIF can also work when the browser and delivery stack support it.

Does Google prefer WebP or AVIF for ranking?

Google does not give a page a direct ranking bonus for a particular image extension. The benefit is indirect: a correctly sized image can reduce transfer and rendering work, while the page still needs useful content, accessible image text, and a good user experience.

BlogImage Formats

JPEG vs PNG vs WebP vs AVIF: Which Format Should You Use?

A practical image-format decision guide for photos, screenshots, transparency, animation, compatibility, and responsive web delivery.

By LessMB Editorial Team · Reviewed by LessMB Technical Editor

Published June 4, 2026Updated August 1, 2026

Updated: August 1, 2026

Short answer: Use AVIF or WebP for many web photos, PNG or lossless WebP for screenshots and exact graphics, and JPEG when compatibility is the deciding constraint. Keep the original master and serve a fallback when the browser, email client, or upload system may not accept the modern format.

There is no single best image format. A format that is efficient for a photograph may be a poor choice for a screenshot, logo, transparent cut-out, email attachment, or print master. The useful decision is not “Which extension wins?” but “Which file keeps the required pixels, reaches the users I care about, and costs the least to deliver?”

The 30-Second Decision Table

Image or destination	Start with	Keep as fallback or source	Why
Website photograph or product image	AVIF or WebP	JPEG master/fallback	Lossy modern formats often reduce transfer bytes; JPEG is widely accepted.
Screenshot with small text	PNG or lossless WebP	PNG master	Lossy artifacts around letters are easy to notice.
Logo or simple icon	SVG, then lossless WebP or PNG	Original vector	Vector artwork scales without raster blur.
Transparent product cut-out	WebP or AVIF after testing	PNG fallback/master	Modern formats can carry alpha; edge quality still needs inspection.
Email attachment or newsletter graphic	JPEG for photos, PNG for graphics	Original source	Email clients and upload systems do not all accept modern formats.
Animated image	WebP, AVIF, APNG, or video	GIF when required	The best choice depends on motion, color, autoplay, and client support.
Print, archive, or editing master	TIFF, PNG, PSD, or RAW	Keep the master untouched	Delivery compression is not a replacement for an editable source.

This table is a starting point, not a benchmark promise. Google’s WebP study reports 25–34% smaller files than comparable JPEG files at equal SSIM in its test sets, and about 26% smaller lossless files than PNG. Those are reference results from a defined methodology, not a guaranteed saving for every image. Google’s WebP compression study explains the datasets and quality comparison.

What Each Format Is Designed to Do

JPEG: the compatibility-first photo format

JPEG uses lossy compression and is a strong fit for photographs with natural gradients and texture. It does not carry an alpha channel, so it cannot preserve a transparent background. It can also produce ringing around sharp text, thin strokes, and flat-color edges when the quality setting is too low.

JPEG remains valuable because it opens in almost every browser, operating system, email client, editor, camera workflow, and upload form. Keep it when you cannot control the receiving software or when a fallback is more important than the last reduction in bytes.

PNG: exact pixels, graphics, and transparency

PNG is lossless. It is a sensible choice for screenshots, diagrams, logos, UI graphics, and images where a pixel-level difference is unacceptable. It also supports transparency and is widely accepted outside the browser.

The trade-off is that PNG is often inefficient for photographic content. A camera photo exported as PNG can be much larger than a visually comparable JPEG, WebP, or AVIF. Lossless compression can only remove redundancy; it cannot throw away detail the way a lossy encoder can.

WebP: a flexible web delivery format

WebP supports both lossy and lossless compression, transparency, and animation. That makes it useful for photos, graphics, transparent assets, and some animated content. It is broadly supported by current browsers, but legacy software, email clients, and specialized upload forms may still require JPEG or PNG.

Use lossy WebP for photographs when small files matter. Use lossless WebP for logos, screenshots, and graphics where the pixels must remain exact. Do not assume the same quality number produces the same result in every encoder; compare the actual exported file.

AVIF: efficient modern delivery with more pipeline trade-offs

AVIF stores AV1 image data in the AVIF container. It supports lossy and lossless images, alpha transparency, animation, HDR, and wide color gamut. MDN describes AVIF as a high-performance option but recommends a fallback because support is less historically deep than JPEG or PNG. See the MDN image format guide and the AVIF specification from AOMedia.

AVIF is a good candidate for large, static photographs when your CDN or build pipeline can encode it ahead of time. It is less attractive when every request triggers a slow conversion, when low-powered devices are a major part of the audience, or when the destination accepts only JPEG or PNG.

Choose by Image Type

Photographs and product images

Create an AVIF and WebP test from the same high-quality source. Compare faces, skin, fabric, gradients, product edges, and dark areas at the actual display size. Use the smaller file only if the visual result remains trustworthy. Keep JPEG as the final fallback if the page must work in older or restricted clients.

The biggest savings often come before the quality slider: remove pixels the layout never displays. A 4,000-pixel source served into an 800-pixel content column can waste more bytes than a modest format improvement can recover.

Screenshots, charts, and diagrams

Start with PNG or lossless WebP. Lossy compression changes high-contrast edges first, so small UI labels can become difficult to read even when the thumbnail looks fine. Crop empty browser chrome before changing quality, and do not downscale a screenshot unless the destination explicitly requires it.

Transparent graphics

PNG, WebP, and AVIF can carry alpha transparency, but “supports transparency” does not mean “renders every edge identically.” Lossy encoding may change the colors around semi-transparent pixels. Test a cut-out on both a light and a dark background, especially when it has a shadow, hair, glass, or a thin outline.

Animation

GIF is widely recognized but limited in color and often heavy. Animated WebP, AVIF, APNG, or a short video may be better for web delivery. The correct choice depends on whether the recipient supports autoplay, whether audio exists, how the first frame behaves, and whether the asset must work in email.

Deliver AVIF and WebP with a Fallback

For HTML images, use <picture> so the browser can choose a source it understands:

<picture>
  <source srcset="hero.avif" type="image/avif" />
  <source srcset="hero.webp" type="image/webp" />
  <img
    src="hero.jpg"
    width="1280"
    height="720"
    alt="A product shown on a desk"
    fetchpriority="high"
  />
</picture>

The fallback <img> still matters. Keep width and height so the browser can reserve space, and use srcset and sizes when different screens need different pixel widths. If an image CDN negotiates formats using the request’s Accept header, verify that the cache varies correctly and that an AVIF response cannot be served to a client that cannot decode it.

A Repeatable Comparison Workflow

Keep the original source file untouched.
Export JPEG, WebP, and AVIF from the same source and at the same target dimensions.
Compare at a similar visual quality rather than comparing arbitrary quality numbers.
Inspect faces, text, edges, gradients, shadows, and transparent areas at 100% and at normal display size.
Record file size, encode time, decode behavior, and accepted destinations.
Publish the format that meets the user’s quality and compatibility requirements, with a fallback where necessary.

Do not compare a 4,000-pixel JPEG against a 1,200-pixel AVIF and call the codec the winner. Dimensions, crop, metadata, chroma subsampling, encoder version, and source generation all affect the result.

Does the Format Affect SEO?

The file extension is not a substitute for useful page content. Format choice can support page experience by reducing work for the browser, but the result depends on image dimensions, resource discovery, server response, layout stability, and the rest of the page. Use descriptive alt text for meaningful images, do not hide important information only inside an image, and measure the published page rather than relying on a file-size claim.

Common Mistakes

Converting every image to AVIF without a fallback.
Using JPEG for screenshots with small text.
Keeping a huge source image and relying on CSS to shrink it.
Re-encoding an already-compressed JPEG instead of returning to the master.
Deleting the original after creating a delivery copy.
Treating quality numbers from different encoders as interchangeable.
Measuring only file size and ignoring decode time, visual artifacts, or compatibility.