JustConvertAll-in-One Convert

Image Format Converter

Convert images between PNG, JPG, and WebP formats instantly in your browser. Adjust quality for JPG and WebP. No upload — files stay on your device.

Drop an image here or click to browse

PNG · JPG · WebP · GIF · BMP

Related Tools

Base64 → Image

Convert Base64 strings or data URIs back to images instantly. PNG, JPG, WebP, GIF — auto-detects format. No upload required.

Image → Base64

Convert images to Base64 data URIs instantly. Supports PNG, JPG, GIF, WebP, SVG. Files never leave your browser.

Image Compare

Compare two images with a draggable before/after slider in your browser. No upload required.

Advertisement

Image format conversion changes the encoding scheme used to store pixel data, which affects file size, quality, transparency support, and browser/application compatibility. The three dominant web image formats differ in their compression approach: PNG uses lossless compression (every pixel is preserved exactly), JPEG uses lossy DCT-based compression tuned for photographs (some detail is discarded in exchange for dramatically smaller file sizes), and WebP uses a modern hybrid algorithm that achieves better compression ratios than either PNG or JPEG at the same visual quality level.

Choosing the right format for each image type has significant impact on web performance. Photographic content (product photos, hero images, backgrounds) should use JPEG or WebP because lossless PNG compression is inefficient for continuous-tone images — a 1MB JPEG might be a 10MB PNG at equivalent quality. Icons, logos, and screenshots with flat colors or text should use PNG or WebP because JPEG compression introduces visible artifacts (blocking, ringing) around sharp edges and text.

This tool performs format conversion using the browser's Canvas API: the source image is drawn onto an offscreen canvas with toBlob('image/jpeg', quality) or toBlob('image/webp', quality) to produce the output. For JPEG conversion, transparent pixels are composited onto a white background because JPEG does not support transparency. WebP conversion preserves transparency. The quality slider controls the compression level for lossy formats: 0.9 (90%) is a good default that produces visually indistinguishable output at significantly smaller file sizes than 1.0.

Common Use Cases

Converting PNG assets to WebP to improve page load performance

WebP images are typically 25–34% smaller than JPEG and 26% smaller than PNG at equivalent visual quality. Converting a website's image assets from PNG or JPEG to WebP reduces total page weight, improving Largest Contentful Paint scores and decreasing bandwidth costs. Google's PageSpeed Insights and Lighthouse explicitly recommend WebP and AVIF over PNG and JPEG. All major browsers have supported WebP since 2020, making it safe for production use.

Converting PNG screenshots to JPEG for email attachments

Screenshot tools default to PNG, which is lossless but produces large files. A 1920×1080 PNG screenshot of a webpage can be 2–5 MB; the same screenshot as JPEG at quality 85 is typically 200–400 KB. When sharing screenshots as email attachments or in Slack, converting to JPEG reduces file size by 80–90% without perceptible quality loss for photographic content, making the attachment faster to send, receive, and view on mobile.

Preparing images for platforms with format restrictions

Some CMS platforms, app stores, and advertising networks only accept specific image formats. Apple App Store screenshots require PNG; Google Play accepts PNG and JPEG; Facebook Ad Manager requires JPEG or PNG with specific file size limits. When a designer provides assets in the wrong format, converting to the required format is the simplest fix. The format converter handles this without requiring Photoshop or GIMP.

How to Use

  1. Drop or click the upload area to open any image file.
  2. Select the target format: PNG, JPG, or WebP.
  3. For JPG and WebP, drag the quality slider to balance file size vs. visual quality.
  4. A live preview updates as you adjust settings.
  5. Click Download to save the converted image — no server upload required.

Format Guide

When to Convert