JPEG vs PNG: Which Image Format Should You Use?

Quick answer

Choose JPEG for photographic delivery when a smaller file is worth some irreversible image loss. Choose PNG when you need lossless raster storage, sharp flat-color edges, interface text, or alpha transparency. Keep the editing master separate from the delivery copy when repeated saves or future revisions matter.

Core format differences
Criteria	JPEG	PNG
Common compression	Lossy DCT-based	Lossless
Photographs	Usually compact	Often much larger
Sharp edges and text	May show artifacts	Preserves exact decoded pixels
Alpha transparency	Not in common JPEG	Supported

What “lossy” and “lossless” mean here

The familiar JPEG process discards some visual information to reduce size. At a sensible setting, the change can be hard to notice in a photograph; aggressive compression can create blockiness, ringing, and smeared detail. Repeatedly opening, editing, and saving a JPEG can introduce additional loss because each new JPEG encode works from pixels that may already contain compression damage.

PNG reconstructs the encoded pixel values without compression loss. That does not make every PNG small or every source image high quality. It means the PNG encoding itself does not approximate the stored pixel values. PNG also supports indexed color, grayscale, truecolor, and optional alpha information.

Match the format to the asset

A format decision by asset type
Asset	Usually start with	Why
Photograph for delivery	JPEG	Continuous-tone imagery usually compresses efficiently with acceptable loss
Screenshot with small text or interface lines	PNG	Lossless storage avoids JPEG ringing around hard edges
Raster logo or overlay needing transparency	PNG	PNG supports alpha transparency
Working file that will be revised repeatedly	Keep a lossless or native master	Do not make repeated JPEG generations the only surviving source

Separate the master from the delivery copy

The best delivery format is not always the best place to keep your only editable source.

For a photograph, keep the original or another appropriate master and export a JPEG for delivery when size matters. For a screenshot or flat raster graphic, PNG can serve both as a lossless source copy and as the delivered file when its size is reasonable. A layered design, vector artwork, or raw photograph may have a better native master format than either JPEG or PNG.

This distinction prevents a common workflow mistake: repeatedly compressing the only copy because the final website or message happens to need JPEG.

Three conversions that do not create quality

JPEG → PNG does not restore discarded detail. The PNG preserves the pixels decoded from that JPEG; it cannot reconstruct information the JPEG encoder already removed.
PNG → JPEG does not preserve PNG-style alpha transparency. A JPEG export must resolve transparent areas into an opaque result.
A larger file is not automatically a better image. Encoding choice, source quality, dimensions, and the intended display or print size still matter.

Renaming is not conversion

Changing a filename from .jpg to .png does not change the encoded image format. A real conversion must decode the source and encode a new file.

A quick workflow

Photo, final delivery, no transparency: export a JPEG and inspect the result at the size people will actually see.
Screenshot, UI capture, diagram, or text-heavy raster: start with PNG.
Overlay or raster graphic that needs smooth transparency: use PNG.
File that will be edited again: keep a separate lossless or native master, even if the delivery copy is JPEG.
Unsure because the image will be printed: format is only one question. Pixel dimensions and final physical size also matter; see DPI vs PPI.

Choosing a JPEG quality setting

JPEG quality is a trade-off controlled by a slider, and the numbers differ between programs, so treat any value as a starting point rather than a standard. In many editors, values in the upper range produce files that look nearly identical to the original at normal viewing sizes, while very low values introduce visible blocks and colour smearing, especially around edges and in smooth gradients like skies.

A practical method is to export two or three versions at different quality levels, view them at the size they will be displayed, and choose the smallest file that still looks right. For a photo shown small on a web page, a lower setting can be perfectly acceptable. For a photo that will be printed or zoomed, the same setting may show defects.

Where newer formats fit

JPEG and PNG are not the only options. Formats such as WebP and AVIF can often produce smaller files than JPEG at comparable visual quality, and WebP can also store transparency. Browser support for them is now widespread, but not every program, email client, or print workflow accepts them. JPEG and PNG remain the safest choices when an image has to open everywhere.

If you are publishing to the web, using a modern format with a JPEG or PNG fallback is a reasonable approach. For documents, uploads to third-party services, and anything sent to a printer, check what the recipient accepts first.

Common mistakes with image formats

One mistake is saving a screenshot of text as JPEG and then wondering why the letters look fuzzy. The compression is tuned for photographs, so hard edges suffer. Another is saving a large photograph as PNG for a web page, which can make the page far heavier than it needs to be and slow it down for visitors on mobile connections.

A third is resizing an image repeatedly by saving over the same JPEG. Each save adds another generation of loss. Resize from the original, keep a master copy, and export a fresh delivery file each time.