JPG, PNG, WebP and AVIF Explained.
JPG, PNG, WebP and AVIF all have different strengths. Learn how they work, how they compare, and which image format makes the most sense for your website.
Choosing an image format can feel more complicated than it should be. You upload a photo and suddenly you're looking at options like JPG, PNG, WebP and AVIF.
They all store images, but they don't work in exactly the same way. Some are better for photographs, some are useful when you need transparency, and some are designed to keep image files small for the modern web.
So which one should you actually use?
Quick answer: JPG is a reliable choice for photographs, PNG is useful when lossless quality or transparency matters, WebP is a flexible modern option for many websites, and AVIF can provide very efficient compression when your workflow and browser support make it practical.
Why Does Image Format Matter?
An image's format affects more than just its file extension. It can influence file size, image quality, transparency, compression and how easily the image fits into your website workflow.
This matters because images can make up a large part of the total data loaded by a webpage.
A huge image doesn't necessarily look better on a visitor's screen. If you can keep the visual quality you need while reducing the amount of data being downloaded, your website can become more efficient.
A widely supported format that works especially well for photographs and other detailed images.
A lossless format that is useful for graphics, screenshots and images that need transparency.
A modern format supporting both lossy and lossless compression, with transparency support as well.
A newer image format based on AV1 technology that can offer very efficient compression and high image quality.
What Is JPG?
JPG, or JPEG, is one of the most familiar image formats on the internet. It has been used for decades and is supported by practically every modern browser, phone, computer and image editing application.
JPG uses lossy compression. In simple terms, some image information is removed during compression to make the file smaller.
When the compression level is reasonable, the difference can be difficult to notice, which makes JPG particularly useful for photographs.
When is JPG a good choice?
- Photographs
- Product photos
- Blog images
- Travel photography
- Images where broad compatibility matters
What Is PNG?
PNG is a popular image format known for lossless compression. Unlike lossy formats, PNG does not throw away image information during normal compression.
One of its biggest advantages is transparency. PNG can store transparent areas, making it useful for logos, interface graphics, screenshots and certain designs.
The trade-off is that PNG files can become considerably larger than JPG, WebP or AVIF when used for photographs.
When is PNG a good choice?
- Logos
- Transparent graphics
- Screenshots
- Interface elements
- Images where lossless quality is important
What Is WebP?
WebP is a modern image format developed by Google. It was designed to provide efficient compression while maintaining good visual quality.
WebP supports both lossy and lossless compression and can also support transparency.
That makes WebP a flexible option for websites. It can be used for photographs, graphics and other images where reducing file size is important.
Why do websites use WebP?
- Good image quality
- Often smaller files than comparable JPG images
- Supports transparency
- Supports lossy and lossless compression
- Strong support in modern browsers
What Is AVIF?
AVIF is a newer image format based on the AV1 image technology. It was designed with efficient image compression in mind.
AVIF can produce very small files while maintaining impressive image quality, which makes it interesting for performance-focused websites.
However, AVIF can have a more complicated workflow than JPG or WebP. Encoding and editing support can vary depending on the software and tools you're using.
When is AVIF worth considering?
- Performance-focused websites
- Modern web applications
- Images where very efficient compression matters
- Workflows that already support AVIF
JPG vs PNG vs WebP vs AVIF
Here's a quick comparison of the four formats and where each one generally fits best.
| Feature | JPG | PNG | WebP | AVIF |
|---|---|---|---|---|
| Lossy compression | Yes | No | Yes | Yes |
| Lossless compression | No | Yes | Yes | Yes |
| Transparency | No | Yes | Yes | Yes |
| Photographs | Excellent | Good | Excellent | Excellent |
| Graphics | Good | Excellent | Excellent | Good |
| Typical file size | Medium | Large | Small | Very small |
| Website use | Good | Good | Excellent | Excellent |
| Compatibility | Excellent | Excellent | Excellent | Good |
Which Image Format Is Best for Websites?
There isn't one format that wins for every type of image. The right choice depends on what you're uploading and what matters most for your website.
For photographs: WebP or JPG
For most website photographs, WebP is a strong modern choice. JPG is still perfectly useful, especially when compatibility is important.
For transparent graphics: PNG or WebP
If transparency is required, PNG and WebP are generally much more suitable than JPG.
For maximum compression: WebP or AVIF
If your priority is keeping image files as small as practical, WebP and AVIF are worth considering.
For maximum compatibility: JPG or PNG
JPG and PNG have been supported for a very long time, so they remain convenient choices when you need a format that works across a wide range of software and workflows.
Which Format Has the Smallest File Size?
AVIF and WebP can often produce smaller files than JPG and PNG for comparable images, but there is no universal file-size winner for every image.
The result depends on the image itself, its dimensions, compression settings and the encoder being used.
A good image optimization workflow is therefore not about blindly converting every image to the newest format.
The real goal is simple: keep the image looking good while using as little file size as reasonably possible.
Does a Smaller Image Mean Lower Quality?
Not necessarily.
Modern image formats can achieve impressive compression while keeping images visually close to the original.
However, every lossy format has a point where additional compression becomes noticeable. If you compress too aggressively, details can become softer and artifacts may appear.
That's why it's worth checking the actual image after compression instead of choosing settings based only on the percentage of file size saved.
How Image Formats Affect Website Performance
Images can account for a significant amount of the data loaded by a webpage.
If your website contains large photographs, banners, product images and thumbnails, reducing those files can reduce the amount of data visitors need to download.
This can be especially helpful for visitors using mobile connections or devices with slower network speeds.
But image format is only one part of the equation. Image dimensions and compression matter too.
- Don't upload unnecessarily large dimensions.
- Compress images before uploading them.
- Choose a suitable format for each image.
- Use responsive images where appropriate.
- Keep image quality high enough for the intended display size.
Which Format Should You Use for WordPress?
If you're using WordPress, WebP is a practical choice for many modern websites.
Instead of uploading a huge original photograph directly to your media library, consider resizing and compressing it first.
Original → Resize → Compress → Convert → Upload
For photographs, WebP can often provide a useful balance between quality and file size. PNG can remain useful for transparent graphics and screenshots.
AVIF can also be a good option if your WordPress setup and image workflow support it properly.
Do WebP and AVIF Help With SEO?
Using WebP or AVIF doesn't automatically improve your search rankings.
However, properly optimized images can help reduce the amount of data a webpage needs to load, which can contribute to a better user experience and overall website performance.
Good image SEO also involves using appropriate dimensions, descriptive alt text, responsive images and sensible compression.
How to Choose the Right Image Format
If you're not sure which format to use, start with the type of image you're dealing with.
- Photo: WebP or JPG
- Transparent logo: PNG or WebP
- Screenshot: PNG or WebP
- Website photograph: WebP
- Very small modern web image: AVIF or WebP
- Maximum compatibility: JPG or PNG
How to Convert Images Between Formats
If you already have JPG, PNG or other image files, you don't necessarily need to recreate them from scratch.
You can convert supported images into another format and then compare the resulting file size and visual quality.
With IMAGE24 Image Converter , you can convert images directly in your browser without installing traditional image editing software.
If your main goal is to make an image smaller, you can also use the IMAGE24 Image Compressor before uploading it to your website.
JPG, PNG, WebP or AVIF: Which One Should You Use?
The answer depends on the image.
JPG remains a reliable choice for photographs and situations where compatibility matters.
PNG is useful when you need lossless quality or transparency, especially for graphics and screenshots.
WebP is an excellent all-round option for many modern websites because it combines good quality, efficient compression and useful features.
AVIF can provide very efficient compression and is worth considering when your website and workflow support it well.
Our simple rule: Use JPG when compatibility is the priority, PNG when transparency or lossless quality matters, WebP for a flexible modern website format, and AVIF when you want very efficient compression and your workflow supports it.
Ready to optimize your images?
Convert your images to a more suitable format or reduce their file size before adding them to your website.
Frequently Asked Questions
WebP is a strong choice for many modern website images because it can provide good image quality with efficient file sizes. JPG, PNG and AVIF can still be better depending on the specific image and requirements.
For many modern websites, WebP can be a better choice because it often provides smaller files at comparable visual quality. JPG remains useful when compatibility is especially important.
Neither format is always better. PNG is useful when lossless quality and transparency are important, while WebP can often provide a smaller file for website use.
AVIF can produce very small files and can outperform WebP for some images, but the actual result depends on the image and encoding settings. It is not guaranteed to be smaller in every situation.
WebP is usually a strong choice for modern website photographs because it can provide good quality with efficient file sizes. JPG remains a reliable alternative when compatibility is the main concern.
PNG and WebP can both support transparency. PNG is a familiar choice for logos, while WebP can often provide a smaller file size for web delivery.
Yes. You can convert supported JPG images to WebP using an image converter. IMAGE24 provides a browser-based image converter for supported image formats.
Simple image tools for everyday image work.