Images Are Usually the Biggest Problem
Unoptimized images are the #1 cause of slow pages. Convert to WebP, compress properly, serve appropriate sizes. Most sites can cut image weight by 70%+ without visible quality loss.
Squoosh
Free, from Google. Browser-based, no upload to servers. Side-by-side quality comparison. Supports WebP, AVIF, MozJPEG, and more. Runs entirely in your browser for privacy. The best tool for manually optimizing individual images.
Manual Compression Tools
Squoosh
USE ITGoogle's browser-based image compressor. Live preview, multiple format support including AVIF. Runs locally in browser—no server upload. Resize, compress, convert. Free and private. The gold standard for manual optimization.
TinyPNG / TinyJPG
USE ITSmart lossy compression for PNG and JPEG. Drag and drop, bulk processing. API available for automation. Excellent quality-to-size ratio. The most popular quick compression tool.
ImageOptim (Mac)
USE ITDesktop app for Mac. Drag and drop, lossless optimization plus optional lossy. Removes metadata, optimizes compression. Free and runs locally. The best option for Mac users who process images regularly.
Automated/API Services
For sites that need to process images automatically.
ShortPixel
USE ITAPI and WordPress plugin. Lossy, glossy, and lossless compression. WebP and AVIF generation. Good pricing for bulk usage. Solid option for WordPress sites or API integration.
Cloudinary
SITUATIONALImage CDN with on-the-fly transformation. Auto-format, auto-quality, resizing via URL params. Good for sites with many images that need dynamic processing. Overkill for small sites, essential for image-heavy applications.
imgix
SITUATIONALReal-time image processing CDN. Similar to Cloudinary but focused purely on images. Powerful URL-based transformations. Good for high-traffic sites with complex image needs.
WordPress Plugins
ShortPixel Image Optimizer
USE ITCompress on upload, bulk optimize existing images, WebP conversion. Good free tier. Reliable and well-maintained. The best overall WordPress option.
Imagify
SITUATIONALFrom WP Rocket team. Good integration if you're already using WP Rocket. Three compression levels. WebP support. Higher cost than ShortPixel for same volume.
Smush
SKIP ITPopular but limited. Free version caps at 5MB and doesn't include WebP. ShortPixel offers better value. Smush Pro is expensive for what you get.
Command Line Tools
cwebp / libwebp
USE IT
Google's official WebP encoder. Command line, scriptable.
cwebp -q 80 input.png -o output.webp
Essential for build pipeline integration.
Sharp (Node.js)
USE ITFast Node.js image processing. Resize, compress, convert formats. Uses libvips for speed. The standard for Node.js image pipelines.
Image Optimization Checklist
- 1. Use WebP (or AVIF) with JPEG/PNG fallback
- 2. Serve correctly sized images (not scaling down in browser)
- 3. Compress to 80-85% quality (usually visually lossless)
- 4. Use lazy loading for below-the-fold images
- 5. Set explicit width/height to prevent layout shift
- 6. Use a CDN for image delivery
Most sites can improve LCP dramatically just by properly optimizing the hero image. Start there.