JPEG (JPG): best for photographs
JPEG is a lossy compression format designed specifically for photographs and realistic images. It works by discarding colour information that the human eye is least sensitive to, achieving file sizes 5–10× smaller than uncompressed images with minimal visible quality loss.
JPEG supports millions of colours and compresses gradients very efficiently — exactly what photographs need. The trade-off is that it degrades every time you save: each save cycle applies another round of compression. Always keep your original and only export to JPEG as the final step.
JPEG does not support transparency. If you need a transparent background, JPEG is the wrong choice.
Best for: product photography, blog post images, hero images, social media photos, anything photo-realistic.
PNG: best for graphics and transparency
PNG uses lossless compression — it reduces file size without throwing away any image data. The result is pixel-perfect quality that never degrades, no matter how many times you save the file. This makes PNG ideal for logos, icons, diagrams, screenshots, and any image containing text.
PNG supports full transparency (alpha channel), which makes it the standard format for logos and interface elements that need to sit on different backgrounds.
The drawback is file size. For photographs, PNG files are 3–5× larger than equivalent JPEGs at the same visual quality. Using PNG for photos adds unnecessary bulk with no visible benefit.
Best for: logos, icons, illustrations, screenshots, UI elements, any image needing a transparent background.
WebP: the modern replacement for both
WebP was developed by Google as a universal replacement for both JPEG and PNG. It achieves JPEG-quality results at 25–35% smaller file sizes using lossy compression, and PNG-quality results at 20–30% smaller file sizes using lossless compression.
WebP also supports transparency (like PNG) and animation (like GIF). It is supported by all modern browsers — Chrome, Firefox, Safari (since 2020), and Edge all handle WebP natively.
The main limitation of WebP is compatibility with older software. Some older image editors, CMSs, and email clients don't support it. If you need broad compatibility, JPEG and PNG remain safe choices.
Best for: web pages where performance matters, modern web apps, any context where you control the display environment.
Quick decision guide
Photograph or realistic image → JPEG (or WebP if browser support is confirmed)
Logo, icon, illustration, or screenshot → PNG (or WebP lossless)
Image with transparency → PNG or WebP
Animation → WebP or GIF
Needs to work in old software or email → JPEG or PNG
Optimising a website for speed → Convert everything to WebP
Format comparison at a glance
Compression: JPEG = lossy, PNG = lossless, WebP = both lossy and lossless
Transparency: JPEG = no, PNG = yes, WebP = yes
Animation: JPEG = no, PNG = no (APNG exists but rarely used), WebP = yes
File size for photos: JPEG = small, PNG = large, WebP = smallest
File size for graphics: JPEG = poor (artefacts), PNG = medium, WebP = smallest
Browser support: JPEG = universal, PNG = universal, WebP = all modern browsers
Summary
For web use, WebP is the best choice whenever browser compatibility allows. For photos going into email or legacy systems, JPEG. For logos, icons, and anything needing a transparent background, PNG. Understanding these three formats takes five minutes and saves hours of troubleshooting blurry images and slow page loads.