PNG vs JPG: what is the difference, and which should you use?

PNG and JPG are the two most common image formats, but they were designed for very different purposes. Choose the wrong one and the image may look blurry or become unnecessarily large. This guide explains the core differences and which format to use for photos, screenshots, icons, and other common content.

The key difference: lossy vs lossless

JPG (JPEG) commonly uses lossy compression. It reduces size by simplifying color and detail and is effective for photographs with continuous tones. Lossy re-encoding of an existing JPG can accumulate artifacts, so keep a lossless working source and make the delivery JPG once at the end.

PNG uses lossless compression. It preserves every pixel, does not lose quality when resaved, and supports transparent backgrounds. The tradeoff is that photos are usually much larger than equivalent JPGs.

Transparency

This is a decisive difference: PNG supports transparency, while JPG does not. Logos, icons, and stickers with transparent backgrounds can use PNG, WebP, or AVIF. When SnapshotLab converts one to JPG, transparent pixels are composited over white, so inspect the edges before download.

Choose by content type

• Photos and realistic images: Use JPG. It handles continuous color and fine detail well at small file sizes.
• Screenshots and interface images: Use PNG for crisp text and edges. JPG can introduce fuzzy artifacts around letters.
• Icons, logos, and line art: Use PNG for limited colors, sharp edges, and transparency.
• Transparent backgrounds: Use PNG, WebP, or AVIF, not JPG.

What about WebP and AVIF?

WebP and AVIF are newer formats that often produce smaller files than JPG or PNG at similar quality. Both support lossy compression, lossless compression, and transparency. They are often better choices for modern browsers when file size matters. For a detailed comparison, see WebP vs AVIF.

How SnapshotLab tests the choice

To avoid generalizing from one image, we review three equal-dimension samples: a photo with skin tones and foliage, an interface screenshot with 12–16 px text and thin lines, and an icon with semi-transparent edges. Export the same source to PNG and JPG, record byte size, inspect photo detail and glyph edges at 100%, and use 200% only to locate artifacts.

1. For the photo, use JPG quality 80 only as a trial starting point and change one setting at a time. Eighty is not a universal optimum.
2. For the screenshot, focus on ringing, color halos, and gradient banding around small text. A smaller JPG fails if readability suffers.
3. For transparency, place output over dark and light backgrounds. JPG cannot satisfy a preserve-transparency requirement, so byte size alone must not decide the result.

Limitations and easy misjudgments

• A small image with few colors and large flat areas can make a smaller PNG. PNG is not always larger than JPG.
• PNG preserves shadows and soft transparency but may become large. Include transparent WebP or AVIF in the test when that happens.
• Do not assume a converter preserves EXIF, location, color profiles, or other metadata. Verify them separately for archival, print, or evidence workflows.

Format references

PNG losslessness and transparency are defined by the W3C PNG Third Edition specification. JPEG standards and official material are available from JPEG.org.

Try it yourself

To convert between PNG, JPG, WebP, and AVIF or make a large image smaller, use the image compressor and converter. It runs locally in your browser without uploading images. To change dimensions, use the image resizer. To combine images into a PDF, use images to PDF. For more compression advice, see the image compression guide.