PNG vs JPEG: When to Use Each Format
Photos vs graphics, transparency, artifacts, and file size — a clear answer to the classic format question.
Two formats built for different jobs
PNG and JPEG are the two most common image formats you'll deal with, and picking the wrong one is the easiest way to end up with an image that's blurry, bloated, or both. The good news: the decision is simpler than most comparison charts make it look. It almost always comes down to what's in the picture, not where the picture is going.
The short version. JPEG uses lossy compression tuned for photographs — it throws away detail your eye is unlikely to notice and produces small files. PNG uses lossless compression — every pixel survives exactly as it was — and it supports transparency, which JPEG doesn't. Nearly everything else in this guide is a consequence of those two facts.
Photos: JPEG, almost every time
Photographs are full of smooth gradients, soft focus, and fine sensor noise — exactly the content JPEG's compression was designed around. At a sensible quality setting, a JPEG of a photo is visually indistinguishable from the original in normal viewing while taking up a fraction of the space. That's why every camera and phone on earth defaults to it (or to a newer lossy format) for photos.
Save the same photo as a PNG and the file balloons, often to several times the size, with no visible payoff. Lossless compression can't take the "close enough" shortcuts that make JPEG efficient; it has to record every grain of noise faithfully, and noise compresses terribly. A PNG photo isn't wrong — it's just expensive. The main reason to keep a photo lossless is as a working master you intend to edit repeatedly.
Screenshots, text, and graphics: PNG
Flip the content and the answer flips. Screenshots, charts, diagrams, logos, UI mockups, pixel art — anything with hard edges, flat areas of color, and especially text — is PNG territory. Lossless compression handles large uniform regions extremely well, so a screenshot saved as PNG is frequently smaller than the same image saved as a high-quality JPEG, and it stays perfectly crisp.
JPEG on this kind of content produces its telltale failure: gray fuzz and faint halos around letters and sharp lines, sometimes called ringing or mosquito noise. The cause is structural. JPEG divides the image into 8-by-8 pixel blocks and approximates each one with smooth waves; a hard black-on-white edge is the worst possible input for that scheme, so the edges shimmer with leftover compression error. No quality setting fully eliminates it — it only makes the fuzz fainter and the file bigger.
Transparency: PNG only
PNG carries a full alpha channel — 256 levels of transparency per pixel — which is why logos, icons, watermarks, and cut-out product shots are almost always PNGs. Drop one onto any background and the edges blend cleanly, including soft partial transparency like drop shadows and anti-aliased curves.
JPEG has no concept of transparency at all. Every JPEG is a fully opaque rectangle, full stop. If your image needs to sit on top of something else — a colored web page, another photo, a slide background — JPEG is off the table no matter how good its file size looks.
Converting PNG to JPEG: what you gain and what you lose
Converting PNG to JPEG makes sense when the PNG contains photographic content — a photo someone exported losslessly, or a screenshot that's mostly a picture. You'll usually get a dramatically smaller file, and a quality setting in the 80–90 range keeps the loss invisible for photos.
Two things don't survive the trip. First, transparency: JPEG can't store it, so any transparent region gets flattened onto a solid white background. A logo floating on a transparent backdrop comes out as a logo in a white box — fine for some uses, ruinous for others, so check before you batch-convert. Second, exact pixel values: the conversion is lossy, which is harmless for photos at high quality but will add visible artifacts around any text or line art in the image.
Converting JPEG to PNG: what it does and doesn't do
Going the other direction is lossless but not restorative. The PNG faithfully records the JPEG's pixels — compression artifacts included — and it cannot recover detail the JPEG already threw away. The file will usually get larger, sometimes much larger, while looking exactly the same.
There are still legitimate reasons to do it. Some upload forms and tools only accept PNG. If you plan to edit an image repeatedly, converting to PNG first stops the slow quality decay that comes from re-saving a JPEG over and over — each lossy re-save discards a little more, while PNG re-saves are free. And if you'll be adding transparency in an editor later, you need a format that can hold it. Just don't expect the conversion itself to sharpen anything.
The practical recommendation
The cheat sheet: if it came out of a camera, use JPEG at quality 80–90. If it came off a screen — text, interface, chart, diagram — use PNG. If it needs transparency, PNG is your only option between the two. If you're unsure, zoom in on any text or hard edge in the image: fuzz and halos mean JPEG compression is hurting it and PNG would serve it better. One aside for the web: if you control the site and only need modern browsers, WebP handles both jobs and is usually 25–35% smaller than JPEG at similar quality.
When you need to convert, Convertmaxxing handles PNG to JPG and JPG to PNG directly in your browser. The conversion runs locally through WebAssembly, so files are never uploaded to a server — relevant if the images are private. It's free and needs no signup. JPEG output includes a quality slider; PNG output doesn't need one, since it's lossless. You can also strip EXIF metadata, including GPS location, during the conversion. And per the note above: transparent areas in a PNG are flattened to white on the way to JPEG, so keep a PNG copy of anything with a transparent background.