The Ultimate Guide to Image Compression for 2023

With increasingly higher resolution images and growing website sizes, image compression has become an essential tool for webmasters, designers, and digital marketers. Optimized images load faster, consume less bandwidth, and improve site performance.

In this comprehensive guide, we’ll cover everything you need to know about effectively compressing images for the web in 2023.

What is Image Compression?

Image compression is the process of reducing the file size of images. It works by eliminating redundant and non-essential data from image files.

There are two main types of image compression:

Lossless Compression

Lossless compression shrinks file size without losing image quality. It does this by removing metadata and optimizing color palettes. Common lossless formats include PNG, GIF, and SVG.

Lossy Compression

Lossy compression achieves much greater reduction in file size by permanently removing less visible image data. JPEG is the most popular lossy format. Though some quality is lost, visually the images look nearly identical.

The right compression technique depends on your specific needs. For photos and detailed images, lossless is preferred. For web graphics, logos, and illustrations, lossy works well.^[1]

Why Image Compression Matters

Optimized images provide a better user experience and benefit SEO. Here are some key reasons to compress your images:

Faster Page Loads

Large image files slow down page loading speed. Compressed images reduce page weight, allowing pages to load faster.^[2]

Better Site Performance

Lighter pages put less strain on your hosting server and bandwidth. Image optimization improves overall site performance.^[3]

Saves Mobile Data

Mobile internet connections are slower and have data caps. Compressed images use less data and load quicker on mobile.<

Improves SEO

Faster load times and lower bounce rates boost search rankings. Image optimization enhances SEO.^[4]

Saves Storage Space

Compressed images take up less disk space on your CMS or CDN. You can store more images using less storage.

Essential Image Optimization Practices

To leverage the benefits of image compression, you need an effective optimization workflow. Here are some key best practices to follow:

Use Proper Image Formats

• JPEG for photos, graphics with complex colors
• PNG for simple logos, illustrations, transparent backgrounds
• GIF for simple animations
• WebP/AVIF for critical above-the-fold images

Adjust Image Dimensions

Scale images to the display size needed, don’t make users download huge images for small thumbnails.

Compress Losslessly First

Use PNGQuant, TinyPNG, or RIOT to optimize images losslessly first.

Compress Lossily If Needed

For JPEG images, use JPEGMini, TinyJPG, or Compressor.io to further reduce size.

Strip All Unneeded Metadata

Remove EXIF, XMP, GPS, camera settings that aren’t needed for the web.

Set Caching Headers

Set expires headers to maximize caching and minimize re-downloads.

Use CDNs and Image CDNs

Distribute images globally from a fast CDN like Optimized24 Image CDN.

Implement Responsive Images

Use srcset and sizes for resolution switching and art direction.

Lazy Load Below the Fold

Only load images in the viewport and lazy load the rest to speed initial load.

Use Image Sprites

Combine small icons into image sprites sheets.

Employ Next-Gen Formats

For hero images, use WebP and AVIF for smaller file sizes.

By following these best practices, you can significantly optimize images across your website for maximum performance.

Image Compression Tools

Manually optimizing images can be extremely tedious and time consuming. Luckily, there are excellent automation tools available to compress images in bulk. Here are the top tools on the market:

Optimized24 Image Optimizer

Optimized24 Image Optimizer is an intelligent AI-powered tool that can losslessly optimize and compress batches of images in seconds. It supports JPEG, PNG, GIF, and PDF formats. The optimized images are perfect for websites with near identical visual quality.

TinyPNG

TinyPNG uses smart lossy compression to reduce PNG file sizes. It has a free web interface and paid API plans.

TinyJPG

TinyJPG provides powerful lossy compression for JPEGs. It also has online and API options.

Smush

Smush is a popular WordPress plugin that can losslessly optimize images uploaded to WordPress sites. It has limited format support.

RIOT

RIOT is an advanced lossless image optimizer supporting PNG, JPEG, GIF, and SVG files. It has Windows and Mac apps.

JPEGMini

JPEGMini specializes in optimizing JPEG images with minimal quality loss. It can drastically reduce image sizes.

Compressor.io

Compressor.io is an API-based service that offers intelligent lossy and lossless image optimization for all formats.

The best option depends on your budget, site setup, and optimization needs. For hassle-free automated image compression, Optimized24 Image Optimizer is highly recommended.

Image Optimization and SEO

Optimized images don’t just improve site speed and performance. They also benefit SEO and boost your search visibility. Here are some of the top benefits:

Better Image SEO

Smaller image sizes reduce page weight which helps pages rank better in Image Search results.^[5]

Faster Crawl Speed

Search engine bots can crawl optimized pages much quicker, leading to faster indexing.

Higher Rankings

Faster load times and lower bounce rates from image optimization improve search rankings.

Increased Engagement

Optimized images enhance user experience and site engagement metrics that search engines value.

Saves Crawl Budget

With compressed images, bots can crawl and index more pages per session.

To maximize SEO, every image on your site should be properly optimized following the steps outlined earlier.

Image File Size Best Practices

Finding the optimal file size for web images requires balancing visual quality and performance. Here are some general image size guidelines to follow:

Hero Images

The large hero banners and photos on homepages and landing pages should be between 50-100 KB. Up to 200 KB is acceptable if WebP/AVIF formats are used.

Page Banners

Top page banners, headers and other large images can be 20-50 KB.

Article Images

Images inserted into page content can be 10-30 KB. Full bleed images can go up to 50 KB.

Thumbnails and Icons

Thumbnail images, user avatars, and icons should be 2-10 KB.

Image Galleries

For ecommerce product catalogs, portfolios, and other image galleries aim for 5-20 KB per image.

The optimal size ultimately depends on your site, layout, resolution, and compression techniques used. Use these recommendations as a general starting point when optimizing.

Image Dimensions and Resolution

In addition to compression, adjusting image dimensions and resolution is key for optimization. Use these best practices:

• Set exact widths for image containers, don’t force users to download full size images for small spaces.
• For high resolution screens, go up to 2560 x 1440 px for the largest images.
• For lower resolution displays, 1920 x 1080 px is sufficient.
• For page banners, 1000 x 500 px or 1200 x 600 px works well.
• Blog and page content images can be 800 x 450 px general web use.
• Generate 2x and 3x resized images for high density displays.
• For print, use 300 PPI. For web, 72 PPI is fine.
• Save SVG vector images as small as possible, don’t rasterize to high resolutions.

By adjusting image dimensions and resolution to your specific needs, your site will be more responsive and pages will load even faster.

Image Format Guide

There are many image formats to choose from, each with their own strengths and weaknesses. Here is an overview of the top formats:

JPEG

Uses: Photos, complex graphics

Strengths: Extremely small files, lossy compression, great for web use

Weaknesses: Quality loss with high compression, artifacts, poor text/vector quality

PNG

Uses: Logos, illustrations, transparent images

Strengths: Lossless compression, excellent quality, full transparency support

Weaknesses: Large file sizes compared to JPEG, not ideal for photos

GIF

Uses: Animations, simple graphics

Strengths: Animation support, full transparency

Weaknesses: Limited colors (256 max), large file sizes, obsolete format

WebP

Uses: Web graphics, critical above-the-fold images

Strengths: Much smaller than JPEG/PNG with no loss

Weaknesses: Browser support not 100% yet, no animation support

AVIF

Uses: Future replacement for JPEG/PNG

Strengths: Cutting edge compression algorithm, 30% smaller than WebP

Weaknesses: Minimal browser support currently, early lifecycle format

Image Metadata

Images contain metadata that is unnecessary for web use. Stripping this metadata significantly reduces file size with no visual quality loss.

EXIF Data

EXIF contains camera settings, GPS location, timestamps and other metadata added by cameras.

XMP Data

XMP holds editing history, color profile, and other metadata from Photoshop and Lightroom.

IPTC Data

IPTC stores captions, keywords, ratings, and other metadata added by users.

Thumbnails

JPEG and TIFF files often contain embedded thumbnail previews that can be removed.

Many image editors and compression tools have options to automatically strip metadata on export and optimization.

Image Loading Speed

In addition to optimization, how you load images impacts page speed. Use these techniques:

Lazy Loading

Only load images visible in the viewport, lazy load the rest on scroll.

Image Sprites

Combine multiple images into sprite sheets. Use CSS to display single images.

Responsive Images

Use srcset and sizes to serve multiple resolution images.

Next-Gen Formats

Serve WebP/AVIF images to supported browsers for better compression.

Image CDNs

Distribute images from blazing fast CDN servers, like Optimized24 Image CDN.

With the right loading strategies, you can further boost page speeds beyond just optimization.

Image Compression Software Compared

Here’s an overview of the top image compression and optimization apps:

This covers the most popular options. The best choice depends on your needs and budget. Optimized24 Image Optimizer provides the best combination of lossy and lossless compression, automation, and affordability.

FAQ

Does image optimization reduce quality?

Lossless optimization maintains full image quality. Minor quality loss only occurs with “lossy” JPEG compression.

Will compressing images improve SEO?

Yes, optimized images improve site speed and UX metrics that directly impact search rankings.

What’s the best image format for website?

Use JPEG for photos, PNG for logos/illustrations, and WebP for critical above-the-fold images.

How can I compress images for free?

Try free tools like TinyPNG, Optimized24 Image Optimizer, and online compressors to optimize images at no cost.

What image size should I use for website?

Hero images 50-200 KB, banners 20-50 KB, page images 10-30 KB, thumbnails under 10 KB.

Conclusion

Optimizing images should be a key step in preparing visual assets for the web. Following the compression techniques and best practices outlined in this guide will help you deliver the best quality images to users in the most efficient way possible.

Smaller image file sizes benefit site performance, user experience, SEO, mobile data usage, and hosting costs. With the rise of high-resolution screens and photography, image optimization is now more important than ever.

Leveraging automated solutions like Optimized24 Image Optimizer makes it easy to optimize hundreds or thousands of images in a fraction of the time manual methods would take. Their intelligent AI-powered platform can losslessly compress images up to 90% smaller with no visible quality loss in just seconds.

By adding image optimization into your workflow, you can provide the fastest, most positive viewing experience and maximize the impact of your visual content.

Use Vector Images When Possible

Vector images like logos and illustrations should be created and saved as SVG for minimal file size and maximum image quality.

Combine Identical Elements

Use CSS sprites to combine identical background elements like icons and buttons into a single image file.

Crop Unneeded Areas

Crop out and remove unnecessary white space and background areas before compressing.

Use Image CDNs

Distribute optimized images globally from a content delivery network to improve load speeds.

Set Expires Headers

Configure long expires headers to allow images to be cached in browsers for faster repeat page views.

Optimize On Upload

Automatically optimize images on upload before they are stored on your site. Don’t optimize manually later.

Monitor Image Performance

Use analytics to monitor image loading times, compressions levels, and other metrics.

Check for Image Crawl Errors

Review image crawl reports in Search Console to fix errors preventing Google from indexing images.

Improve Image File Paths

Use optimized image filenames and folder structures to improve internal site linking and SEO.

Minify and Inline Small Images

Very tiny images can be base64 encoded and inlined into CSS to avoid extra HTTP requests.

Use WebP Images

Leverage WebP image support to take advantage of improved lossless and lossy compression capabilities.

By combining a variety of optimization techniques, you can find the right balance between image quality, performance and SEO. Advanced solutions like Optimized24 Image Optimizer make the process easy and efficient.

Audit Current Images

Do an audit of all images on your site to identify optimization opportunities.

Create Image Guidelines

Define standards for image dimensions, formats, and compression to maintain consistency.

Adopt Best Practices

Follow industry best practices for alt text, file naming, aspect ratios, etc.

Improve Page Grouping

Optimize image heavy pages by splitting into multiple pages or tabs.

Balance Image Density

Aim for a reasonable image density, don’t oversaturate pages with too many visuals.

Monitor Broken Images

Check for broken images regularly and reupload optimized versions.

Validate Sitemaps

Ensure image sitemaps contain only accessible optimized images.

Optimize Catalog Images

Ecommerce sites should optimize product category, collection and catalog images.

Compress User Generated Content

Optimize and compress UGC images submitted through forms.

Add Lazy Loading

Lazy load offscreen images to optimize page loading sequences.

Use Background Images

Replace some inline images with CSS background images for better control.

Employ Responsive Designs

Responsive designs display properly sized images for each device and layout.

Use Efficient Themes

Choose lightweight WordPress themes with optimized code for faster image loading.

Install Caching Plugins

Caching plugins like WP Rocket speed up image delivery and page loads.

Optimize Media Library

Use the Regenerate Thumbnails plugin to bulk optimize existing images.

Pick Optimized Hosting

Host WordPress sites on optimized hosts like Kinsta or WPEngine for better performance.

Configure PHP

Tune PHP settings like memory limit and max execution time for processing large images.

Add CDN Integration

Integrate a content delivery network like Optimized24 Image CDN to accelerate image delivery.

Scale Down Large Images

When uploading massive images, scale them down to a reasonable web size.

Strip Metadata on Upload

Use a plugin like Metadata Striper to automatically remove useless EXIF data.

Convert Images to WebP

WebP images can drastically reduce image sizes. Use a WebP converter plugin.

Optimize Images Before Upload

Use desktop tools like RIOT to optimize images before uploading them to WordPress.

By following WordPress-specific image optimization tips, you can overcome common problems with bloated images slowing down your site.

Use Optimized Themes

Choose lightweight Shopify themes with modern image handling and lazy loading.

Enable Media Image Optimization

Shopify’s built-in image optimization provides basic compression.

Install Apps

Apps like Image Engine or Pixelz provide advanced image optimization.

Strip Metadata

Use apps to automatically remove useless EXIF data upon upload.

Resize Large Images

Don’t upload massive product images. Resize them to appropriate dimensions first.

Use Automatic Resizing

Shopify can automatically resize images to multiple sizes for devices and layouts.

Employ Responsive Designs

Shopify themes are mobile-friendly out of the box with responsive image handling.

Configure Image Loading

Set image loading order and logic in theme code for optimal sequences.

Limit Image Numbers

Avoid saturating product pages with too many overload images. Stick to what’s needed.

Add Image CDNs

Speed up image delivery by integrating a fast CDN like Optimzied24 Image CDN.

Monitor Image Performance

Keep track of image size, compression, and page loading data. Continuously optimize.

With smart configurations and apps, Shopify stores can deliver optimized lean images for maximum conversions.