The "PNG or JPG?" question looks trivial, but the wrong answer leaves you with either a needlessly huge file or visible quality loss. The entire difference comes from one technical distinction: JPG uses lossy compression, PNG uses lossless.
What lossy and lossless actually mean
To shrink a file, JPG permanently discards some image information. It discards the details the human eye notices least — which is why a photo can shrink by 70% and still look identical. PNG discards nothing; it simply encodes the file more efficiently. A PNG is always pixel-identical to the original, but produces far larger files for photographs.
Which one, when?
| Use case | Pick | Why |
|---|---|---|
| Photograph (landscape, portrait, product) | JPG | Loss is invisible in smooth gradients; file shrinks 60-90% |
| Logo, icon, emblem | PNG | Preserves hard edges and transparent background |
| Screenshot containing text | PNG | JPG creates blurry smudges around letters |
| Image with transparent background | PNG | JPG cannot store transparency at all — it fills with white |
| Photo to attach to an email | JPG | Stays under size limits |
| Graphic going to print | PNG | Lossless — every detail survives |
Transparency: the most common mistake
JPG technically cannot store transparency. When you convert a PNG with a transparent background to JPG, transparent regions become white (or black in some tools), and this cannot be undone. Anyone who has saved a logo as JPG and then tried to place it on a dark background has seen that white box.
If you need transparency and file size matters, there is a third option: WebP. It supports transparency and is meaningfully smaller than PNG. Every modern browser supports it.
Why PNG for screenshots?
JPG compression struggles with sharp contrast transitions. Text is exactly that: a black pixel next to a white one. The result is blurry grey smudges around letters, known as compression artifacts. The same screenshot saved as PNG looks sharper and is often smaller too — screenshots contain few flat colours, and PNG is very efficient with that kind of content.
A practical decision rule
- Does the image have transparency? → PNG (or WebP)
- Does it contain text that must stay readable? → PNG
- Is it a photograph? → JPG
- Will you edit it repeatedly? → Work in PNG, export JPG
- Still unsure? → Produce both and compare size and appearance
That last point is more practical than it sounds: conversion takes seconds, so producing both and putting them side by side is genuinely the fastest way to decide. All the tools below run in your browser — your files are never uploaded to any server.