Reducing image file size is not just a matter of dragging a quality slider downward. A better process starts by asking what the image is for.
1. Fix dimensions first
If a website displays an image at roughly 1200 pixels wide, uploading a 6000-pixel camera original wastes bandwidth. Resize the delivery copy to a sensible maximum dimension while keeping the original elsewhere.
2. Pick a format that matches the content
Photographs usually compress well with JPEG, WebP or AVIF. Screenshots, logos and graphics with transparency may fit PNG or a lossless modern format better. Converting a photo to PNG can make it much larger without improving visible quality.
3. Adjust compression gradually
Compare the image at normal viewing size. Lower quality in steps and stop before artifacts become distracting. The right setting depends on texture, sharp edges and how closely users inspect the image.
4. Remove unnecessary metadata when appropriate
Metadata can include camera information, thumbnails and other fields. Removing unneeded metadata can reduce size and sometimes improve privacy, but do not remove information your workflow actually needs.
5. Test the result
Measure bytes, inspect quality and test where the image will actually appear. The best optimization is the smallest file that still meets the visual and compatibility requirements of the real use case.