Bolt storage

Image Compression and Optimization Not Working in Bolt App

Your Bolt.new application loads images at full resolution regardless of display size, causing slow page loads, excessive bandwidth usage, and poor Core Web Vitals scores. A 5MB profile photo is served at 4000x3000 pixels even though it's displayed at 100x100 on the page.

Bolt's AI typically generates basic img tags or stores images exactly as uploaded without any processing. This means a user uploading a 10MB DSLR photo gets that exact 10MB file served to every visitor, even on slow mobile connections.

The problem compounds quickly: a page with 20 user-uploaded images can require 50MB+ of downloads, making your app unusable on mobile and destroying your Google PageSpeed score. Image optimization is one of the biggest performance wins for any web application.

Error Messages You Might See

LCP (Largest Contentful Paint) exceeded 4 seconds Warning: Image with src has no width or height Error: sharp module not found in production net::ERR_CONTENT_LENGTH_MISMATCH (large image transfer failed)
LCP (Largest Contentful Paint) exceeded 4 secondsWarning: Image with src has no width or heightError: sharp module not found in productionnet::ERR_CONTENT_LENGTH_MISMATCH (large image transfer failed)

Common Causes

  • No image processing on upload — Images are stored at original resolution and format without server-side resizing or compression
  • Missing Next.js Image component — Using plain <img> tags instead of Next.js <Image> which provides automatic optimization
  • No lazy loading — All images load eagerly on page load, even those below the fold that aren't visible yet
  • Wrong image format — Serving PNG or JPEG instead of modern WebP or AVIF formats that are 30-50% smaller
  • No responsive sizing — Serving the same large image regardless of the user's screen size or viewport

How to Fix It

  1. Use Next.js Image component — Replace <img> with <Image> which auto-optimizes: <Image src={url} width={400} height={300} quality={80} />
  2. Compress on upload — Process images server-side before storage using sharp: sharp(buffer).resize(1200, 1200, { fit: 'inside' }).webp({ quality: 80 }).toBuffer()
  3. Use Supabase image transforms — Serve optimized images via transform URL: supabase.storage.from('images').getPublicUrl(path, { transform: { width: 400, quality: 80 } })
  4. Add lazy loading — Add loading="lazy" to images below the fold, or use the IntersectionObserver API for custom lazy loading
  5. Generate multiple sizes — Create thumbnail, medium, and full-size versions on upload and serve the appropriate one using srcset
  6. Set proper cache headers — Configure Cache-Control: public, max-age=31536000, immutable for static image assets

Real developers can help you.

Simon A. Simon A. I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows. Basel Issmail Basel Issmail ’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems. My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale. In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals. I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software. Alvin Voo Alvin Voo I’ve watched the tech landscape evolve over the last decade—from the structured days of Java Server Pages to the current "wild west" of Agentic-driven development. While AI can "vibe" a frontend into existence, I specialize in the architecture that keeps it from collapsing. My expertise lies in the critical backend infrastructure: the parts that must be fast, secure, and scalable. I thrive on high-pressure environments, such as when I had only three weeks to architect and launch an Ethereum redemption system with minimal prior crypto knowledge, turning it into a major revenue stream. What I bring to your project: Forensic Debugging: I don't just "patch" bugs; I use tools like Datadog and Explain Analyzers to map out bottlenecks and resolve root causes—like significantly reducing memory usage by optimizing complex DB joins. Full-Stack Context: Deep experience in Node.js and React, ensuring backends play perfectly with mobile and web teams. Sanity in the Age of AI: I bridge the gap between "best practices" and modern speed, ensuring your project isn't just built fast, but built to last. Sage Fulcher Sage Fulcher Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them) Dor Yaloz Dor Yaloz SW engineer with 6+ years of experience, I worked with React/Node/Python did projects with React+Capacitor.js for ios Supabase expert Vlad Temian Vlad Temian 15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox). Cursor ambassador and agentic tooling builder. I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti. I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks. https://blog.vtemian.com/ Matt Butler Matt Butler Software Engineer @ AWS hanson1014 hanson1014 Full-stack developer experienced in fixing and deploying AI-generated apps from Lovable, Bolt.new, Cursor, and Replit. I specialize in debugging Supabase integration issues (auth flows, RLS policies, database connections), fixing broken deployments, resolving routing/blank screen problems, and cleaning up messy React/Vite codebases. I also build production apps with the Claude API and have shipped a Mac desktop dev tool (Nexterm from scratch. Based in Hong Kong, fast turnaround. PawelPloszaj PawelPloszaj I'm fronted developer with 10+ years of experience with big projects. I have small backend background too Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.

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Frequently Asked Questions

What image format should I use for web?

Use WebP as the default format - it provides 30% smaller files than JPEG at the same quality. For maximum compression, use AVIF (50% smaller than JPEG). Always provide a JPEG fallback for older browsers using the picture element.

How do I optimize images already in my storage bucket?

Use Supabase's built-in image transformation API to serve optimized versions without re-uploading. Add transform parameters to your getPublicUrl call: { transform: { width: 800, format: 'webp', quality: 75 } }.

Related Bolt Issues

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