JPG vs PNG: Which Image Format Should You Use?

JPG and PNG are the two most common image formats on the internet, and they are both excellent — but for different types of content. Understanding the difference between them saves you from large, unnecessary files on one hand and poor-quality images on the other.

The core difference: lossy vs. lossless compression

The most important difference between JPG and PNG is how they handle compression — the process of making a file smaller.

JPG uses lossy compression. When you save an image as JPG, the encoder analyses the image and permanently removes image data that is statistically unlikely to be noticed by the human eye. The more compression applied, the smaller the file — and the more data is discarded. This is irreversible. Each time you save a JPG, more data is discarded. For photographs, this trade-off is usually invisible at typical compression levels, but it becomes very visible at high compression (small file sizes) or after many re-saves.

PNG uses lossless compression. PNG reduces file size by finding mathematical patterns in the pixel data and encoding them efficiently — but without discarding any data. The original pixel information is preserved completely, no matter how many times the file is saved. This makes PNG files larger than JPG for most photographic content, but the image is mathematically identical to the original every time.

When to use JPG

JPG is the right choice when:

• You are working with photographs. Real-world photos contain millions of subtly varying colours, which JPG compresses very efficiently. A photo that is 8 MB as PNG might be only 1.5 MB as a JPG with no perceptible quality difference.
• File size matters more than perfect quality. For website images, social media uploads, and email attachments, smaller is better. JPG's lossy compression achieves dramatically smaller files.
• Transparency is not needed. If your image has a solid background and you don't need any transparent areas, JPG's lack of transparency support is not a problem.
• The image will not be edited repeatedly. If you are sharing a final photo rather than working file, JPG is appropriate.

When to use PNG

PNG is the right choice when:

• You need transparency. Logos, icons, stickers, and interface elements typically need to sit on different coloured backgrounds. Only PNG (and WebP, SVG, GIF) support true transparency. A company logo on a transparent background must be PNG.
• The image has sharp edges, flat colours, or text. JPG compression creates visible "artefacts" (blurry halos, blocky areas) around sharp edges and text. PNG preserves these perfectly. Screenshots, diagrams, and illustrations look much better as PNG.
• You will edit the image multiple times. Because PNG is lossless, you can save it dozens of times with no quality loss. Use PNG as your working format and export to JPG only for the final version.
• Accuracy is critical. Medical images, scientific illustrations, maps, and technical diagrams should use lossless formats to avoid any distortion.

A practical decision guide

How to convert between JPG and PNG

Converting between the two formats is straightforward:

• PNG to JPG: Use the PNG to JPG converter. Note that transparent areas will be filled with white in the output JPG, and there will be slight quality loss due to lossy compression.
• JPG to PNG: Use the JPG to PNG converter. The PNG will be lossless going forward, but it cannot recover quality that was already lost in the original JPG — it preserves what is there, without degrading it further.

Neither conversion adds transparency automatically — that requires image editing software. These tools change the compression method, not the image content itself.