Use JPG for photographs and PNG for graphics, screenshots, and transparency. That single rule resolves most format decisions. The reasoning behind it comes down to numbers: a 12 megapixel photo saved as PNG weighs 2 to 8MB, while the same photo as JPG lands between 200 and 800KB with no difference your eyes can detect. Flip the content, though, and the advantage flips with it. A flat-colour logo saved as JPG grows fuzzy halos around its edges that PNG never produces. This guide explains what each format actually does, where each one breaks, and which to choose for photos, logos, screenshots, print, and the web.

What is a PNG file?

PNG stands for Portable Network Graphics, a format released in 1996 as a patent-free replacement for GIF. It compresses losslessly using the DEFLATE algorithm, the same method ZIP archives use, so every single pixel survives saving and re-saving without change. PNG also carries an alpha channel, a fourth value per pixel that controls opacity from fully invisible to fully solid. Two common variants exist: PNG-8 limits the palette to 256 colours and keeps files tiny for simple graphics, while PNG-24 stores millions of colours for richer images. Screenshots, logos, icons, charts, and interface mockups all play to PNG's strengths. Photographs do not, and that's where its rival takes over.

What is a JPG file?

JPG (identical to JPEG, short for Joint Photographic Experts Group) arrived in 1992 and was engineered for one job: making photographs small. It divides an image into 8 by 8 pixel blocks and discards colour detail that human vision barely registers, a process called lossy compression. A quality dial from 0 to 100 controls how aggressive the discarding gets. At the top of that dial the loss is invisible; at the bottom, images turn blocky. The trade has a hard cost: JPG has no alpha channel, so it cannot hold a transparent background, and the data it throws away never comes back. How much smaller does that trade actually make your files? The numbers are striking.

File size: the real-world numbers

File size is where the two formats diverge most sharply, and the winner depends entirely on content:

A smartphone photo: roughly 4MB as PNG, 300 to 500KB as JPG at quality 90. JPG wins by a factor of ten.
A full-screen desktop screenshot: 2 to 5MB as PNG, around 400KB as JPG. JPG wins on size, though text edges soften slightly.
A two-colour logo, 500 by 500 pixels: about 8KB as PNG-8, 25KB or more as JPG with visible edge noise. PNG wins on both size and appearance.
A gradient-heavy chart: results vary, and it's worth testing both.

So neither format is "the small one" universally. Photographic content compresses dramatically better as JPG; flat graphics with few colours often compress better as PNG. Size is only half the story, because each format also fails differently.

Image quality: where each format breaks

Quality problems show up in opposite places. JPG's weakness is sharp, high-contrast edges: black text on white, thin lines, hard borders. Aggressive compression scatters faint speckles (called ringing artifacts) around those edges, which is why a heavily compressed screenshot looks smudged even when a photo at the same setting looks fine. JPG also suffers generation loss: every edit-and-save cycle re-compresses the image and stacks new damage on old. PNG has neither problem. Its weakness is purely weight; perfection costs megabytes. The third difference between the formats isn't about quality at all. It's about what happens behind the image.

Transparency and the alpha channel

Transparency belongs to PNG alone in this comparison. Its alpha channel lets a logo float over any page colour, which is why web designers export interface assets as PNG by default. Convert that file to JPG and the see-through region must be flattened to a solid colour, white by default in our converter, with black and custom fills available. We cover the mechanics in detail in our transparent background guide. With the three core differences established, the choice for any given file becomes mechanical.

When to use PNG

Reach for PNG in these situations:

Logos and icons, where edges must stay razor sharp at any compression level.
Screenshots you'll annotate or re-edit, because repeated saves cost nothing.
Images needing transparency: watermarks, overlays, floating graphics.
Charts, diagrams, and text-heavy graphics, where compression speckle would hurt readability.
Master copies of anything you might modify later.

When to use JPG

Choose JPG for these jobs:

Photographs headed anywhere: web, email, social, storage.
Upload forms on government portals and job sites, which frequently demand JPG and enforce caps like 100KB or 200KB.
Email attachments, where a ten-image batch needs to fit under the 25MB ceiling Gmail and Outlook impose.
Website content images, since lighter pages rank and convert better.
Archiving finished photos at quality 90 or above, trading invisible loss for an enormous storage saving.

Which is better for your website?

Website performance favours JPG for every photographic asset. Page weight feeds directly into Largest Contentful Paint, one of Google's Core Web Vitals, and swapping PNG photos for JPG copies is often the single biggest one-step saving available on an image-heavy page. Keep PNG for the pieces that need it: logos, icons with transparency, and UI elements. Modern sites increasingly serve WebP or AVIF, which beat both classic formats on compression, but JPG remains the universal fallback that opens everywhere, from decade-old browsers to office software. Whatever mix you settle on, you'll eventually need to move images from one format to the other.

How to convert between PNG and JPG

Converting takes three steps in our free browser-based tool: drop in your PNG files, pick a quality level or an exact target size, and download the results. Processing happens on your own device with nothing uploaded. Going the other direction (JPG to PNG) is technically trivial but rarely useful, since wrapping already-compressed pixels in a lossless container recovers nothing and inflates the file. Our quality guide covers the exact settings worth using.

Frequently asked questions

Is PNG higher quality than JPG?

Yes for graphics, effectively no for photos. PNG is mathematically perfect because nothing is discarded, but on a photograph viewed at normal size, a JPG saved at quality 90 looks identical while weighing a tenth as much.

What does lossless compression mean?

Lossless compression means the file shrinks without discarding any pixel data, so decompressing restores the image exactly. Lossy compression shrinks further by permanently removing detail the eye is unlikely to miss.

Which format should I use for logos, photos, and screenshots?

Logos take PNG, photos take JPG, and screenshots depend on destination: keep PNG while editing, convert to JPG for sharing or uploading.

PNG or JPG for printing?

Either prints well at high resolution, but print shops usually prefer JPG because the files transfer faster and their colour pipelines expect it. Export at quality 95 or above so compression stays invisible on paper.

Why are my PNG files so large?

Because lossless storage of photographic detail is expensive. Millions of subtly different colours give the DEFLATE algorithm almost nothing to compress, so the format ends up storing nearly raw pixel data.

Does converting JPG to PNG improve quality?

No. The detail JPG discarded is gone permanently, and a PNG wrapper just preserves the damaged version in a bigger file.

Which image formats support transparency?

PNG, WebP, AVIF, and GIF support transparency; JPG and BMP do not. PNG offers the smoothest alpha blending of the older formats.

Is WebP better than PNG and JPG?

On compression, yes: WebP files run 25 to 35 percent smaller than equivalent JPGs and support transparency too. JPG still wins on universal compatibility with older software, which is why both remain everywhere.

Still deciding? Run a copy of your image through the PNG to JPG converter and compare the result side by side with the original. The right answer is usually obvious within seconds, and it costs nothing to check.