JPG vs PNG: Which Image Format Should You Use?

JPG and PNG are the two image formats most people meet every day, and choosing the wrong one is the most common reason an image looks fuzzy, weighs too much, or shows an ugly white box around a logo. The short version: JPG is built for photographs, PNG is built for graphics with flat colour, sharp edges or transparency. The rest of this guide explains why, and what really happens to your file when you convert between them.

How JPG stores an image

JPG (also written JPEG) is a lossy format. It divides the picture into small blocks and throws away fine detail that the human eye is least likely to notice, mainly subtle colour changes and very high-frequency texture. On a photograph of a landscape or a face this works extremely well, because natural images are full of gradual gradients. A 12-megapixel phone photo, 4032 by 3024 pixels, typically ends up between 2 and 5 MB as a JPG.

The same technique performs badly on hard edges. Look closely at a JPG screenshot of a spreadsheet and you will often see faint speckles around the letters. Those speckles are compression artifacts, and the lower the quality setting, the more visible they become. JPG also has no transparency, so every pixel must have a colour.

How PNG stores an image

PNG is lossless. Every pixel you put in comes back out exactly, which makes it the right container for screenshots, interface mockups, diagrams, charts, logos and anything with text. PNG also supports an alpha channel, meaning pixels can be fully or partly transparent. That is what lets a logo sit on a coloured web page without a white rectangle around it.

The price is size. The same 12-megapixel photo saved as a PNG is often 15 MB or more, because the format has to remember every tiny variation in the sky and skin tones. PNG shines when the picture has large areas of identical colour, because those compress to almost nothing.

A quick way to choose

• Photograph for the web, email or social media: JPG.
• Screenshot containing text or interface elements: PNG.
• Logo, icon or sticker that needs a transparent background: PNG.
• Image you plan to edit again several times: PNG, or keep the original, because every JPG re-save loses a little more detail.
• Image that must stay under a strict size limit: JPG, then reduce the quality or dimensions.

What conversion can and cannot do

Converting a JPG to a PNG does not bring back detail that the JPG already discarded. The result is a lossless copy of a lossy picture. It will be larger than the original and look identical. There are still good reasons to do it: some editing programs and upload forms insist on PNG, and a PNG copy will not degrade further if you open and save it repeatedly.

Going the other way, from PNG to JPG, is where people lose things without noticing. The ConvertFusion PNG to JPG tool fills any transparent area with white, because JPG cannot store transparency. If your logo had a see-through background, the JPG will have a white background instead. That is fine for a document, and wrong for a website header on a dark page. Keep the PNG original for those cases.

Both converters on this site work inside your browser. The picture is drawn onto a canvas and re-encoded, which has two side effects worth knowing. First, camera metadata such as the date, device model and GPS location is not copied into the new file, so a converted image is somewhat more private than the original. Second, colour profiles may not be carried across, so an image prepared in a wide-gamut profile can look slightly different afterwards. For ordinary web and document use you will not notice either effect.

Common mistakes

Saving a screenshot as JPG. Text edges blur and the file is often not even smaller. Use PNG for screenshots.

Saving a photograph as PNG for the web. The page becomes slow for no visible benefit. A JPG at around 80 percent quality looks the same to most viewers and is a fraction of the size.

Renaming the extension. Changing photo.png to photo.jpg in your file manager does not convert anything. The data inside is still PNG, and some programs will refuse to open it. Use a real converter.

Converting back and forth. JPG to PNG to JPG gains nothing and costs quality at the final JPG step. Pick the right format once and keep the original file.

A simple test you can run yourself

Take one photograph and one screenshot of a web page. Convert both with JPG to PNG and PNG to JPG, then compare the file sizes in your file manager. You will usually see the photograph grow dramatically when it becomes a PNG, while the screenshot stays modest as a PNG and shows faint blurring around the text when saved as a JPG. Seeing it with your own files makes the rule easy to remember.

What about WEBP?

WEBP can do both jobs: it has a lossy mode for photographs and a lossless mode with transparency for graphics, usually at a smaller size than either JPG or PNG. Current versions of the major browsers can display it. If you publish images on a website, our guide on converting PNG to WEBP explains when the switch is worth it. For email attachments, printing and uploading to older systems, JPG and PNG remain the safest choices.

Summary

Use JPG for photographs where small size matters, and PNG for anything with text, sharp lines or transparency. Convert only when a destination requires it, always keep the original, and remember that converting cannot restore detail that was already lost.