Why convert PNG to JPG?
PNG is the dominant format for screenshots, graphics, and images that need transparency. According to the HTTP Archive's Web Almanac 2024, PNG is used on approximately 77% of websites — more than any other format. But PNG is lossless, which means photo-style PNG files are often 3–5× larger than an equivalent JPEG. For sharing photos by email, uploading to social media, or posting to listing sites like eBay or Airbnb, JPG is the practical choice.
JPG is universally supported: every device, OS, email client, and web form that accepts images accepts JPEG. If you have a PNG photo and need to send it somewhere with a file-size limit, converting to JPG is usually the fastest path to a smaller, compatible file.
Convert PNG to JPG without uploading
LocalJPG converts PNG files entirely in your browser using the native createImageBitmap and OffscreenCanvas APIs, then re-encodes the result as JPEG via MozJPEG at quality 85. No data is transmitted to a server — the file is decoded and re-encoded entirely on your device.
This is particularly useful for screenshots of internal dashboards, design files with proprietary content, or any image you'd rather not send to a third-party service. Open DevTools → Network before dropping a file and the request log will stay empty.
PNG vs JPG: transparency and file size
PNG supports transparency (alpha channel); JPEG does not. When you convert a PNG with a transparent background to JPG, the transparent areas are filled with white. For logos, icons, or design assets that need to sit on coloured backgrounds, PNG is the right format — don't convert those. For photos and screenshots of user interfaces (which have a solid background anyway), the transparency difference is irrelevant and the file-size saving from JPEG is significant.
The built-in resize tool lets you set a target file size after conversion — useful when you need to hit a specific upload limit. Enter a maximum in kilobytes and LocalJPG will binary-search the optimal JPEG quality automatically.
Batch converting PNG files
Drop a folder of PNG images and the converter processes them in parallel using a background Web Worker. Individual JPGs are free to download one at a time. To download all converted files as a single ZIP, a one-time $0.50 unlocks the batch export for that session. The ZIP is assembled in-browser with streaming compression — no server involved at any point.
Also available: HEIC to JPG, WebP to JPG, AVIF to JPG