Why Does (Image) Size Matter?

A visually appealing website is crucial to attract and retain visitors. High-quality images play a significant role in enhancing user experience and conveying your brand’s message. However, using improperly optimized images can lead to low page speed scores, and frustrated users, and can negatively impact your website’s performance. In this guide, we’ll walk you through the importance of optimizing images and provide actionable tips to ensure your website remains both visually stunning and fast.

Why Image Sizes Matter: Large, unoptimized images can result in longer loading times, causing visitors to lose patience and potentially navigate away from your site. Search engines like Google factor in page speed for search rankings, so a slow website can also impact your online visibility. By optimizing image sizes, you can strike the right balance between visual appeal and performance, ensuring a seamless browsing experience for your audience. Image file sizes should be kept as small as possible without compromising on quality.

Earthling suggests that the combined weight of all images on a single page should be at most 10MB.


Website image size guidelines

The best image size for websites varies depending on several factors, including the type of website, its design, and the devices it will be accessed from. However, here are some general guidelines to help you determine optimal image sizes for different use cases:

Background Images
For full-width background images, a common guideline is to use images around 1920 pixels wide by 1080 pixels tall (commonly referred to as Full HD or 1080p resolution). This ensures the image covers the most common screen sizes without excessive cropping or stretching. Remember, too, that if your team wants to feature a slider on the home page, each of those images adds to the page’s weight.

Header Images
Header images, such as banners or hero images, should generally have a width of around 1200 to 1600 pixels. The height can vary based on your design, but a common range is 300 to 600 pixels. If the design of the site features text with an overlay that obscures the image, this is a place to reduce the image quality because it’s not as important as the text on top.

Content Images
Images within your content should be responsive to different screen sizes. A guiding principle is to upload images with a width of around 800 to 1000 pixels, although the design will greatly determine this. Careful consideration needs to be made relative to the other images in the design and on the page. This is especially important on a product page, for example, if there are multiple images per product in addition to showing other related products and their images.

Image formats for the web

The choice of image format for the web depends on the type of image and its intended use. Here are some of the best image formats commonly used for web design:

JPEG is the most widely used image format on the web, particularly for photographs and images with complex color gradients. It offers a good balance between image quality and file size compression. JPEG supports a high level of compression, making it suitable for images with a wide range of colors and details. However, repeated editing and saving of JPEG images can lead to a loss of quality.

PNG is a versatile format often used for images with transparency, simple graphics, icons, and logos. It supports lossless compression, meaning you can save and edit the image multiple times without losing quality. PNG-8 is a variant that supports up to 256 colors and is great for simple graphics, while PNG-24 offers higher color depth and is better for images with transparency. 

GIF is commonly used for simple animations and images with limited color palettes. It supports transparency and animation, making it ideal for small icons, buttons, and graphics. However, GIF’s color palette is limited to 256 colors, making it less suitable for photographs or images with gradients.

SVG is a vector-based image format that is ideal for logos, icons, and graphics that need to scale seamlessly across different screen sizes. SVG files are lightweight, resolution-independent, and can be scaled without loss of quality. They also support interactivity and animation through CSS and JavaScript.

WebP is a modern image format developed by Google that offers both lossy and lossless compression. It typically provides better compression than JPEG and PNG, resulting in smaller file sizes without significant loss of image quality. However, browser support for WebP may vary, and using a fallback format for unsupported browsers is recommended.

AVIF is a newer image format that also offers impressive compression while maintaining high image quality. Like WebP, AVIF files can be significantly smaller than JPEG and PNG files. However, similar to WebP, AVIF support is still evolving and may not be universally supported by all browsers.

The choice of format depends on your specific needs, including the type of image, desired compression level, need for transparency, and the level of browser support you require. It’s common to use a combination of formats across your website to optimize different types of images for the best balance between visual quality and performance.

In a digital landscape where user experience and performance go hand in hand, optimizing image sizes is a non-negotiable aspect of website management. Earthling Interactive emphasizes that by implementing these image optimization strategies, you can strike the perfect balance between captivating visuals and rapid loading times, ensuring your website stands out in today’s competitive online market. For expert assistance in optimizing your website’s images and overall performance, get in touch with Earthling Interactive today!