Fixing a Slow Shopify Store: A Full Image Compression & WebP Strategy
Client: A mid-sized Shopify store in the “home decor” niche with 5,000+ product images.
Challenges We Faced
The client’s beautiful store was slow, especially on mobile, which was killing their Core Web Vitals and conversion rates:
Failing Page Speed & Core Web Vitals
Google PageSpeed Insights showed a mobile score of 28. The LCP (Largest Contentful Paint) was over 7 seconds.
High Mobile Bounce Rate
Google Analytics 4 (GA4) showed an 85% bounce rate on mobile product pages.
Large File Sizes
A Comprehensive Image Audit found 5,000+ uncompressed PNG/JPG images (many over 1MB each).
No Next-Gen Formats
The site was not serving modern, fast-loading WebP or AVIF images.
Low Conversion Rate
Slow-loading product pages were causing a high rate of cart abandonment.
Speed Up Your E-commerce Store
“Is your slow store killing your conversions? Our image compression service and WebP conversion will pass Core Web Vitals and boost your sales.”
Our Approach – How We Solved These Challenges
Comprehensive Image Audit
We used Screaming Frog to crawl the entire site and export a list of all images over 200KB.
Image Compression Service
We used a premium image optimization service (like ShortPixel) to bulk-compress all 5,000+ existing images, reducing their file size by an average of 70%.
Next-Gen Formats (WebP, AVIF)
We configured their Shopify app to automatically convert all images to the WebP format and serve them to compatible browsers.
Image Resizing Service
We fixed their theme’s Liquid code to create responsive images that served the correctly sized file for mobile, tablet, and desktop.
Results
| Metric | Before | After | Growth |
|---|---|---|---|
| Google PageSpeed Score (Mobile) | 28 | 92 | +228% |
| Core Web Vitals (Mobile URLs) | “Failing” (90% URLs) | “Good” (95% URLs) | Passed |
| Mobile Conversion Rate | 0.6% | 1.8% | +200% |
Free Image Speed Audit
“Not sure why your site is so slow? Claim a Free PageSpeed Audit and let our image optimization service company find your large files!”
Advice for Marketers & Brand Owners
- Large images are the #1 killer of page speed and Core Web Vitals.
- Use an Image Compression Service (like ShortPixel or TinyPNG) to bulk-optimize your entire media library.
- Convert to Next-Gen Formats (WebP, AVIF). This offers the single biggest file size reduction while maintaining quality.
- Lazy Loading Implementation is essential for pages with many images (like blog or category pages) to pass the LCP metric.
Extra Factors That Made It Work
- The switch to WebP alone cut the average page weight by over 60%.
- The Lazy Loading implementation was the key to passing the LCP (Largest Contentful Paint) Vitals.
- Our image resizing service ensured mobile users weren’t loading 2000px-wide desktop images.
