Choose the right format, dimensions and compression quality for an image that loads faster and still looks good.
Start with dimensions
An image that is 4000 pixels wide is often unnecessarily large for a small website thumbnail. Resize it to the dimensions where it will actually be displayed, then inspect the result at 100% zoom.
Choose the correct format
JPEG is usually effective for photographs. PNG is useful when graphics need lossless edges or transparent areas. WebP can be an efficient web-delivery format when your target applications support it.
Adjust quality progressively
Compression is a trade-off. Start around 75–85% quality for a photo and adjust while comparing faces, text and fine textures. The right setting depends on your image, so there is no universal perfect number.
Avoid repeated re-encoding
Every lossy re-export can introduce additional artifacts. Keep an original master file and generate delivery formats from that source rather than from an already compressed copy.
Check your actual result
Verify the file size and look closely at the image after downloading. If an upload form has a strict limit, aim slightly below it to allow for differences in file-size interpretation.