How to Prepare Images for Websites Without Making Them Blurry
Website image optimization is a balance: enough pixels for the display, an efficient format, and sensible compression. Oversized files slow pages, while aggressive resizing or compression makes them look soft.
Size for the largest real display
Measure or estimate the largest width the image will occupy. A content image displayed at 800 CSS pixels may need a larger source for high-density screens, but it rarely needs the full dimensions of a modern camera.
Avoid repeatedly enlarging a small source. Start from the best available original, create delivery variants, and let the website choose an appropriate size when its framework supports responsive images.
Match format to image type
Use JPG or lossy WebP for photographs. Use PNG for transparency and sharp interface graphics when file size remains reasonable. WebP is a strong modern delivery format, but keep editable originals in their best source format.
A format conversion is not enough by itself. A 5000-pixel WebP can still be wasteful, and a tiny overcompressed JPG can still look poor.
Compress after resizing
Resize and crop first, then compress the final dimensions. Starting around 75–85% quality often works for photographs, but inspect the actual image. Text, gradients, skin, foliage, and fine patterns reveal problems differently.
Use a byte target only when the platform sets one. For a normal website, visual quality and total page weight matter more than forcing every image to the same KB value.
Prevent layout and accessibility problems
Reserve width and height so the page does not jump while images load. Use meaningful alt text for informative images and empty alt text for purely decorative ones. Lazy-load images below the first viewport, but do not delay the main image that determines the page's largest contentful paint.
Optimization is complete only after checking the page on a phone and a larger screen. Make sure crops still make sense, text embedded in images remains readable, and the browser is not downloading a much larger file than it displays.
- Use the best available source.
- Crop for composition.
- Resize for real display needs.
- Choose JPG, PNG, or WebP deliberately.
- Compress, inspect, and test the finished page.