Home /
Tutorials / The 3 Best Image Formats for Website Performance
Choosing the right image format is crucial for your website’s performance and user experience. Twenty years ago, formats like GIF and JPG dominated due to their simplicity and compatibility. However, with advancements in web technology, newer formats have emerged. In this article, we will explore the categories, formats, and gold standards of image formatting as concisely as possible (we don’t like reading long articles either!).
Categories of Image Formats:
Bitmap (Raster) Graphics: Images made up of a grid of pixels.
Vector Graphics: Images created using mathematical equations and geometric shapes.
Let’s cut to the chase and explain the best three image formats to use in 2024.
1. WebP
Stands for: Web Picture Format
Type: Bitmap
Pros: High compression efficiency, supports both lossy and lossless compression, includes transparency (alpha channel), and supports animations.
Cons: Not universally supported by all browsers and image editors, though support is widespread.
Where to use it: Ideal for general web images, product photos on e-commerce sites, and animated graphics. For example, use WebP for optimising images on a blog or for dynamic content on a retail website.
2. AVIF
Stands for: AV1 Image File Format
Type: Bitmap
Pros: Superior compression efficiency compared to WebP and JPEG, supports HDR, transparency, and offers higher quality at smaller file sizes.
Cons: Still relatively new, not as widely supported by older browsers and image editing software.
Where to use it: Ideal for high-quality photographs, images needing transparency, and scenarios where small file sizes with high image fidelity are essential. For example, use AVIF for portfolio sites, detailed photography, and web backgrounds.
3. SVG
Stands for: Scalable Vector Graphics
Type: Vector
Pros: Scalable without loss of quality, small file size, ideal for logos, icons, and illustrations, supports interactivity and animation.
Cons: Not suitable for detailed images like photographs, complex images can become large and slow to render.
Where to use it: Best for logos, icons, infographics, and interactive web elements. For example, use SVG for a website’s logo or interactive maps and diagrams.
The Other Common Formats
These formats have specific use cases but are not the gold standard for web development in 2024.
4. JPG (JPEG)
Stands for: Joint Photographic Experts Group
Type: Bitmap
Pros: Excellent for photographs due to lossy compression, small file size, widely supported.
Cons: Lossy compression can reduce image quality, does not support transparency.
5. GIF
Stands for: Graphics Interchange Format
Type: Bitmap
Pros: Supports simple animations, widely supported, good for simple graphics with limited colours.
Cons: Limited to 256 colours, not suitable for detailed images, larger file sizes for high-quality images.
6. BMP
Stands for: Bitmap
Type: Bitmap
Pros: Simple and widely supported, uncompressed format ensures no loss of quality.
Cons: Very large file sizes, not suitable for web due to slow loading times.
7. TIFF
Stands for: Tagged Image File Format
Type: Bitmap
Pros: Lossless compression, excellent for high-quality prints and professional photography.
Cons: Large file sizes, not supported by all browsers, slow loading times.
8. PNG
Stands for: Portable Network Graphics
Type: Bitmap
Pros: Lossless compression, supports transparency (alpha channel), good for detailed images and images requiring sharp edges and text.
Cons: Larger file sizes compared to lossy formats like JPG, not suitable for very large images due to file size.
Where to use it: Perfect for images needing transparency, detailed graphics, and images with text. For example, use PNG for website headers, detailed icons, and images with text overlays.
9. PDF
Stands for: Portable Document Format
Type: Vector (can include bitmaps)
Pros: Ideal for documents, maintains formatting across different devices, supports interactivity.
Cons: Not primarily an image format, larger files for image-heavy documents, requires a viewer plugin or software.
10. EPS
Stands for: Encapsulated PostScript
Type: Vector
Pros: Excellent for high-quality prints and scalable graphics, supports transparency.
Cons: Larger file sizes, not suitable for web use due to limited browser support.
11. AI
Stands for: Adobe Illustrator
Type: Vector
Pros: Ideal for creating and editing vector graphics, widely used in professional design.
Cons: Proprietary format, not suitable for web use without conversion, requires Adobe Illustrator to edit.
What Size Should They Be?
The ideal image size depends on the application, but there are general guidelines to follow for optimal web performance:
WebP: For general use, aim for images around 1920 pixels wide for full-width images. For smaller elements like thumbnails, 300-600 pixels wide is typically sufficient.
AVIF: For high-quality images, use around 1920 pixels wide for full-screen images. For smaller graphics like icons, 300-600 pixels wide works well.
SVG: Since SVGs are vector-based and scalable, they don’t have a set resolution. However, ensure the aspect ratio fits your design and avoid overly complex SVGs to keep file sizes manageable.
A good website will automatically resize, scale, and optimise images based on the device and display size. Therefore, using a larger format around 1920 pixels wide ensures that the images are clear on high-resolution screens. Always check with your web developer for specific recommendations and implementation details to ensure optimal performance and quality.
General Guidelines
Full-width images: 1920 pixels wide
Medium images: 800-1200 pixels wide
Thumbnails/icons: 100-600 pixels wide
These guidelines help maintain a balance between image quality and loading speed. Your website should handle resizing and optimisation, so starting with a large, high-quality image ensures the best results across all devices.
Conclusion
While WebP, AVIF, and SVG stand out as the top choices for web development in 2024 due to their balance of quality, file size, and compatibility, other formats like JPG, GIF, BMP, TIFF, PNG, PDF, EPS, and AI have specific use cases that make them valuable in particular scenarios. Understanding the strengths and limitations of each format helps in selecting the right one for any given task.