The image format you choose affects page load speed, visual quality, and storage size. For most web projects, you're choosing between three formats: JPEG, PNG, and WebP. Each has a specific use case, and picking the wrong one means either larger files than necessary or quality loss you didn't need to accept.
JPEG: Photos and Complex Images
JPEG uses lossy compression — it permanently discards some image data to achieve smaller file sizes. The compression works by reducing detail in areas where the human eye is less sensitive, particularly in color transitions and fine textures.
Use JPEG for:
- Photographs and photorealistic images
- Images with many colors and gradual gradients
- Any image where a slight quality reduction is acceptable in exchange for a smaller file
Don't use JPEG for:
- Images with sharp edges, text, or line art (compression artifacts become visible)
- Images that need a transparent background
- Images you'll edit and re-save repeatedly (each save degrades quality further)
A typical high-quality JPEG photo at 80–85% quality is a reasonable default for web use. Going higher rarely produces a visible improvement; going lower produces noticeable artifacts.
PNG: Transparency and Sharp Graphics
PNG uses lossless compression — the full original data is preserved, so the image looks identical to the source at any zoom level. The tradeoff is larger file sizes.
Use PNG for:
- Logos, icons, and UI elements
- Images with text
- Screenshots
- Any image that needs a transparent background (PNG supports full alpha transparency)
- Images where pixel-perfect accuracy matters
Don't use PNG for:
- Photographs (the lossless compression isn't needed, and files are much larger than JPEG)
- Large hero images or backgrounds
A PNG photograph can easily be 5–10x larger than the equivalent JPEG. For photos, the extra size buys you nothing visible.
WebP: Usually the Best Choice for the Web
WebP is a modern format developed by Google that supports both lossy and lossless compression — better than JPEG in lossy mode, better than PNG in lossless mode, and with full alpha transparency support.
Lossy WebP produces files roughly 25–35% smaller than equivalent JPEG files at the same visual quality.
Lossless WebP produces files roughly 25% smaller than equivalent PNG files.
Use WebP for:
- Virtually any image on a website or web app
- Replacing both JPEG and PNG in most cases
- Thumbnails, product images, hero images, blog photos
Browser support is now excellent: Chrome, Firefox, Edge, and Safari (since version 14) all support WebP. If you need to support very old browsers, you can use a <picture> element with a JPEG or PNG fallback:
<picture>
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Description">
</picture>
Format Comparison at a Glance
Format Compression Transparency Best For
JPEG Lossy No Photos
PNG Lossless Yes Graphics, logos, text
WebP Both Yes Almost everything on the web
A Practical Decision Framework
- Is it a photograph or complex image with no transparency needed? → WebP (lossy), with JPEG fallback
- Does it need a transparent background? → WebP (lossless), with PNG fallback
- Is it a simple graphic, icon, or logo with few colors? → WebP (lossless) or PNG
- Does it contain text that must be sharp at all sizes? → SVG (if vector) or PNG
What About AVIF, HEIC, and Other Formats?
AVIF is a newer format with even better compression than WebP, but browser support is still catching up. HEIC (Apple's photo format) has very limited browser support outside Safari. For production web use today, WebP hits the right balance of compression, quality, and compatibility.
To convert images to WebP or between other formats, use the WebP Converter. To compress your images without changing format, use the Image Compressor.