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

Quick answer

Use JPG for widely compatible photographs, PNG for lossless graphics or transparency, WebP for a modern balance of quality, size, transparency and broad browser support, and AVIF when very efficient modern compression is valuable and your target software supports it. There is no single best format for every image.

The fastest decision

If you only need a rule of thumb:

The important point is to choose based on content and destination, not fashion.

JPG

JPEG/JPG is one of the most established formats for photographs.

It uses lossy compression. That means the encoder can discard image information to achieve a smaller file.

Good for

• photographs;
• product imagery;
• email attachments;
• marketplace uploads;
• broad compatibility.

Weak points

• no conventional alpha transparency;
• repeated lossy re-encoding can accumulate artifacts;
• sharp text and line art can look worse than in lossless formats.

For a normal photograph that has to work in unknown software, JPG remains a very safe choice.

PNG

PNG is a lossless raster format.

The W3C PNG specification supports grayscale, truecolor, indexed color and optional alpha transparency.

Good for

• screenshots;
• UI;
• diagrams;
• graphics with sharp edges;
• images that need transparency;
• lossless intermediate files.

Weak points

A full-color photograph stored as PNG can be much larger than a sensibly compressed JPG, WebP or AVIF.

That does not make PNG “bad.” It means lossless storage is not always the most efficient choice for continuous-tone photography.

WebP

WebP supports both lossy and lossless modes, along with transparency and animation.

It is now supported by current major browsers.

Good for

• website photos;
• website graphics;
• transparency;
• situations where you want a modern general-purpose web raster format.

Weak points

Older software outside the browser ecosystem may still handle JPG or PNG more predictably.

If the destination is unknown, compatibility can matter more than theoretical compression efficiency.

AVIF

AVIF is another modern image format designed for efficient compression.

It can support features such as transparency, animation and higher bit depths.

Good for

• modern web delivery;
• bandwidth-sensitive image delivery;
• projects where you control the supported browser/software baseline.

Weak points

Compatibility in older or specialized software can still be weaker than JPG and PNG.

Encoding can also be computationally heavier depending on the implementation and settings.

Which format gives the best quality?

“Quality” needs context.

PNG is lossless, but a lossless 4 MB file is not automatically more useful than a visually excellent 300 KB modern web image.

Likewise, AVIF can compress efficiently, but that does not mean every AVIF encoder setting beats every WebP or JPEG setting.

Compare:

• the same source image;
• the same output dimensions;
• similar visual quality;
• the actual target device/software.

That is much more useful than comparing extensions in isolation.

Which format gives the smallest file?

There is no guaranteed winner for every source.

File size depends on:

• dimensions;
• image complexity;
• encoder;
• quality setting;
• alpha channel;
• metadata;
• bit depth;
• animation;
• whether the mode is lossy or lossless.

Modern formats such as WebP and AVIF often outperform older formats for web delivery, but a specific result should be measured rather than assumed.

Best format for screenshots

PNG is a strong default because screenshots often contain:

• text;
• sharp edges;
• flat colors;
• UI elements.

Lossy compression can create ringing or smearing around these edges.

Lossless WebP can also work well if the destination supports it.

Best format for photographs

For universal sharing: JPG.

For a modern website: WebP or AVIF, usually with an appropriate fallback strategy when required.

MDN recommends considering modern raster formats such as WebP and AVIF for efficient web delivery while accounting for browser/support requirements.

Best format for transparency

PNG, WebP and AVIF can support transparency.

Standard JPEG does not provide the alpha transparency workflow people expect from PNG.

If you convert a transparent PNG to JPG, the transparent area must therefore be flattened to a background.

Should you convert all old images to AVIF?

No.

Do not convert simply because a format is newer.

Conversion can introduce:

• quality loss;
• compatibility changes;
• metadata changes;
• more complexity in your publishing pipeline.

Convert when there is a concrete benefit.

How to compare formats with ReFormatic

Use the same source image and create several outputs:

• JPG;
• PNG;
• WebP;
• AVIF.

Keep dimensions constant.

Then compare:

• file size;
• visible detail;
• transparency;
• compatibility in the destination.

That experiment tells you more than a generic “format X is best” rule.

Bottom line

Choose JPG for compatibility and photos, PNG for lossless graphics and transparency, WebP as a versatile modern web format, and AVIF when efficient modern compression fits your compatibility requirements.

The best format is the one that preserves what matters while working reliably in the next step of your workflow.

Related ReFormatic pages

• JPG to WebP
• PNG to WebP
• AVIF to JPG
• WebP to PNG
• PNG to JPG transparency guide

Try it with ReFormatic

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