Remove pixels nobody will display
Export close to the maximum size the layout needs. Downscaling a large camera image can dramatically reduce weight while improving the apparent sharpness of the final web asset.
Use the right format
Photos usually compress efficiently as WebP or JPG. Logos, diagrams, and screenshots with flat color may need PNG or WebP to keep edges clean. A poor format choice forces you to trade too much quality for a small file.
Compare critical details
Check eyes, text, edges, gradients, and brand colors. Test at 100% zoom and at the intended page size. If the difference is invisible in context, the smaller result is normally the better delivery asset. Always preserve the untouched original.