You have a folder of PNG files that needs to be JPGs — for an upload form that only accepts JPG, for a website where image size matters, or just because someone asked. The conversion takes seconds and is completely free, but there are a few things worth understanding first to avoid common mistakes.
This guide covers the practical differences between PNG and JPG, when to use each format, what happens to transparent images when you convert them, and how to do the conversion for free in a browser.
These two formats were designed for very different purposes, and they each excel at what they were built for.
PNG (Portable Network Graphics) uses lossless compression — every pixel in the original is preserved exactly. PNG also supports transparency, which is essential for logos, icons, and graphics that sit on different background colours. The trade-off is file size: photographs saved as PNG are usually 5–10 times larger than the same image saved as JPG.
JPG (or JPEG) uses lossy compression — it discards information the human eye is unlikely to notice. This produces much smaller files for photographic content with complex colours and gradients. JPG does not support transparency (any transparent area becomes solid colour during conversion). It is the universal default for photographs on the web.
Use PNG when you have:
Use JPG when you have:
A typical 2 MB PNG photograph becomes roughly 200–400 KB when converted to JPG at 90% quality — an 80% size reduction with no visible difference at normal viewing sizes.
This is the catch that surprises people. JPG cannot store transparent pixels. When you convert a PNG with transparent areas to JPG, the converter has to fill those areas with something solid — almost always white. If your PNG logo had a transparent background, the JPG version will have a solid white background.
This is fine when the image will sit on a white page anyway (most websites, most documents), you just need a smaller file, or the transparency was never being used. It is a problem when you want to place the logo on a coloured or photographic background, or when the recipient specifically needs a transparent version (graphic designers, print shops, web developers).
If transparency matters, stay with PNG or convert to WebP, which supports both transparency and high compression.
The entire process — even for 20 files — takes under a minute. Your images never leave your device, so the conversion works fine on confidential photos, personal documents, or unreleased designs.
Approximate sizes for the same image saved as PNG vs JPG at quality 90:
For an e-commerce site with 50 product images, converting from PNG to JPG can reduce total page weight by 60+ MB. This translates directly into faster page loads and better Core Web Vitals scores.
Will I lose quality converting PNG to JPG?
At quality 90 or higher, the loss is invisible at normal viewing sizes — even on high-resolution screens. JPG compression discards information the human eye is unlikely to notice. Drop below 75 and you may start seeing artifacts on close inspection.
Can I convert a JPG back to PNG?
Yes, but it does not restore the original PNG quality. Once JPG compression has been applied, the discarded information is gone forever. Converting JPG to PNG just gives you a PNG file containing the JPG-quality image.
What background colour replaces transparency?
White, by default. This works for most uses where the image will sit on a white page. If you need a different background colour, edit the PNG in an image editor first to flatten transparency against your chosen colour, then convert.
Is there a file size limit?
20 MB per file, up to 20 files at once. For typical photos and web graphics, this is more than enough. If your PNG is larger than 20 MB, it may have unnecessarily high resolution — try resizing first.
Use our free PNG to JPG tool — works in your browser, nothing to install.
PNG to JPG — Free