AVIF to JPG: The Definitive Guide for Performance and Compatibility

1.1 What is an AVIF File (AV1 Image File Format)?

AVIF is a modern image encoding format developed by the Alliance for Open Media (AOMedia), a consortium that includes giants such as Google, Microsoft and Amazon. Its main advantages are:

• Compression Efficiency: AVIF can reduce the size of an image file by more than 50 percent compared to a JPG of similar quality, and about 30 percent compared to WebP.
• Higher Quality:It supports advanced features such as High Dynamic Range (HDR), 10- and 12-bit color depths, and transparency (alpha channel), offering richer and more detailed colors.
• Royalty-Free:Because it is an open standard, its use does not require payment of licenses, a crucial factor for large-scale adoption.

1.2 The trusted JPG (Joint Photographic Experts Group)

The JPG (or JPEG) format has been the de facto standard for photographs on the Web for decades. Its strength lies in its universal compatibility: every browser, device and image software in the world can open it. It uses "lossy" compression, which allows for smaller file sizes by discarding visual information that the human eye perceives with difficulty.

1.3 Important note: AVIF is not AVI

It is easy to confuse acronyms, but it is essential to clarify: AVIF is a format for images, while AVI (Audio Video Interleave), from which the structure of this article is inspired, is a container format for video, developed by Microsoft. Although AVIF is derived from the AV1 video codec, its purpose is to handle static and animated images, not complex video files with multiple audio tracks like AVI.

3.1 Method 1: Online Converters (Fast and Simple)

For one-time or occasional conversions, online tools are perfect. They require no installation and work directly in the browser.

Recommended Tools:

• Squoosh.app (by Google): A powerful tool that shows a real-time preview of file quality and size. Upload the AVIF image and select "JPG" from the drop-down menu for output, adjusting the quality slider.
• FreeConvert: It also allows bulk (batch) conversion of multiple files at once.
• CloudConvert: Another reliable service that supports over 200 formats.

Pro: Extreme ease of use, no software to install. 
Contra:Not ideal for sensitive files (privacy depends on the service), limitations on file size, not automatable.

3.2 Method 2: Desktop Software (Full Control)

For more control over quality, offline bulk conversions, and for working on large files, desktop software is the best choice.

Recommended Tools:

• GIMP (GNU Image Manipulation Program): An open-source, free alternative to Photoshop. Recent versions natively open AVIF files. Just open the image and use the File > Export as... menu to save it in JPG format. Available for Windows, macOS and Linux.
• Adobe Photoshop:With the appropriate "AVIFFormat" plugin (often to be installed separately), it allows you to open and save in AVIF.

3.3 Specific Guide: Opening and Converting AVIF on Windows

1. Enabling Native Support: The first thing to do on Windows 10/11 is to install the "AV1 Video Extension" from the Microsoft Store. This free Microsoft component allows the File Explorer, Paint and Photos app to preview and open .avif files.
2. Converting with GIMP:
   • Download and install GIMP.
   • Open GIMP, go to File > Open and select your AVIF file.
   • Once the image is open, go to File > Export as....
   • In the dialog box, type a name for the file ending in .jpg (e.g., image.jpg).
   • Click on "Export." A window will appear where you can choose the quality of the JPG (a value between 85 and 95 is a good compromise).
   • Confirm to save the file.

3.4 Specific Guide: Converting on Linux from the Command Line

For Linux users, especially developers, the command line offers unparalleled power and flexibility, especially for bulk conversions.

3.4.1 AVIF to JPG Conversion

The tool of choice is ImageMagick, a very powerful suite for image manipulation.

1. Install ImageMagick:

   On Debian/Ubuntu-based systems:

   sudo apt update && sudo apt install imagemagick

   On Fedora/CentOS-based systems:

   sudo dnf install ImageMagick

2. Conversion of a single file:

   Open the terminal, navigate to the folder containing the image and use the magick command:

   magick input.avif -quality 90 output.jpg

   The -quality flag allows you to specify the compression level of the JPG (from 1 to 100).

3. Batch conversion (batch):

   To convert all .avif files to a JPG format folder, you can use a simple for loop:

   for file in *.avif; do magick "$file" -quality 90 "${file%.*}.jpg"; done

   This command takes each file ending in .avif, converts it to JPG while keeping the same base name, and saves it in the same folder.

3.4.2 Creating AVIF files from other formats (JPG, PNG, WebP)

To create AVIF files, we can use two very powerful tools: ImageMagick (with the `mogrify` command for in-place operations) and avifenc (the reference encoder, for more granular control).

1. Install avifenc (libavif):

   On Debian/Ubuntu-based systems:

   sudo apt update && sudo apt install libavif-bin

2. Recursively convert WebP to AVIF with ImageMagick:

   ImageMagick's `mogrify` command is great for bulk conversions. This example converts all `.webp` files in the current folder to AVIF format with 50% quality.

   mogrify -quality 50 -format avif "*.webp"

3. Recursively convert PNG and JPG to AVIF with avifenc:

   avifenc offers advanced control over encoding. These scripts search for all files with PNG, JPG, JPEG extensions and convert them to AVIF, creating a new file with the extension .avif.

   For PNG (case-insensitive) files:

   for file in *.[Pp][Nn][Gg]; do
       avifenc "$file" "${file%.*}.avif"
   done

   For JPG and JPEG files (case-insensitive):

   for file in *.[Jj][Pp][Gg] *.[Jj][Pp][Ee][Gg]; do
       avifenc "$file" "${file%.*}.avif"
   done

4. Supply scripts for maximum efficiency:

   To perform all conversions in one go, you can combine loops. This script finds and converts all common image formats to AVIF within the current directory.

   #Converts JPG, PNG, and WebP to AVIF using avifenc for best compression
   for file in *.[Jj][Pp][Gg] *.[Jj][Pp][Ee][Gg] *.[Pp][Nn][Gg] *.[Ww][Ee][Bb][Pp]; do
       # Check if the file exists before attempting conversion.
       if [ -f "$file" ]; then
           avifenc "$file" "${file%.*}.avif"
       fi
   done

3.5 Method 3: Automation for Developers (Scalability)

For enterprises, manual conversion is not an option. The solution is to automate the process at the infrastructure level.

• Backend Libraries: Integrate libraries such as Sharp (for Node.js) or Pillow (for Python) into your applications. You can create functions that, when uploading an image, automatically generate and save both AVIF and JPG versions.
• Content Delivery Network (CDN): This is the most modern and efficient approach. Services such as Cloudflare (with Image Resizing) or Cloudinary can be configured to intercept image requests. Based on the Accept header sent by the browser, the CDN decides in real time which format to serve, converting the image on the fly if necessary. This completely abstracts the complexity from the developer.
• NginX Web server: it is possible to serve images in different formats based on the user's browser support. By script-creating multiple versions of the image for AVIF, WebP, from JPG and PNG sources, NginX is able to serve the version with the most advanced format supported by the client's browser.

• HTML with the : This HTML tag allows you to specify multiple sources for an image, letting the browser choose the first one it supports. It is the correct semantic solution for the frontend.

  <picture>
     <source srcset="image.avif" type="image/avif">
     <source srcset="image.webp" type="image/webp">
     <img src="image.jpg" alt="Image description">
  </picture>