Step-by-step instructions
- 1
Choose the right format for your image type
Photographs (complex scenes, gradients): use WebP (primary) + JPG (fallback). Logos, icons, illustrations with flat colours: use SVG if vector, or PNG if raster. Screenshots and UI graphics: use WebP or PNG. Animated graphics: use WebP animated or GIF (for email/Slack compatibility). Transparent images: use WebP or PNG. Rule of thumb: WebP for everything photographic, PNG for everything with sharp edges and transparency.
Go to converter - 2
Resize to the display dimensions
Upload images at the size they'll be displayed, not at original camera resolution. A 3000×2000 camera photo uploaded for a 600px-wide blog image is 25× larger than needed. Standard sizes: hero images 1920×1080, article images 1200×800, thumbnails 400×300, product images 800×800. Use an image editor to resize before converting — smaller dimensions mean proportionally smaller files regardless of format.
- 3
Convert JPG/PNG to WebP for web delivery
Go to formatdrop.com/jpg-to-webp or formatdrop.com/png-to-webp. Upload your resized image and download the WebP version. WebP is typically 25–35% smaller than JPG and 26% smaller than lossless PNG at equivalent quality. All modern browsers support WebP. Use the HTML <picture> element with a JPG fallback for maximum compatibility.
- 4
Implement properly in your website code
Use the HTML <picture> element: <picture><source srcset="image.webp" type="image/webp"><img src="image.jpg" alt="description"></picture>. This serves WebP to browsers that support it and JPG to others. Also add loading="lazy" to images below the fold, and set explicit width and height attributes to prevent layout shifts (a Core Web Vitals factor).
Why convert JPG to WebP?
Google's Core Web Vitals (CWV) metrics — used in search ranking — include Largest Contentful Paint (LCP), which measures how quickly the largest visible element (usually an image) loads. Serving unoptimized images directly degrades LCP scores, which can affect search rankings and user experience. The three levers for image optimization are: (1) Correct format — WebP/AVIF instead of JPG reduces sizes 25–50%. (2) Correct dimensions — serving a 400px thumbnail at 3000px resolution wastes 56× the bandwidth. (3) Compression — encoding at quality 80–85 instead of 100 reduces sizes by 50–70% with no perceptible quality change. Applying all three can reduce total page image weight from 10 MB to under 1 MB — a 10× improvement that dramatically affects page load times.
Your files never leave your device
FormatDrop runs the conversion engine entirely inside your browser using WebAssembly. No file upload. No server. Nothing stored. You can verify this by opening DevTools → Network tab and watching: zero upload requests.
Frequently asked questions
What is the best image format for websites?
Should I use WebP or AVIF?
How do I serve WebP with a JPG fallback?
What resolution should web images be?
No account. No upload. Works in any browser.