Images shape first impressions, but a large image can quietly make a page frustrating on a mobile connection. The goal is not to remove visual character; it is to give each image the right job and the right weight.
Choose before you compress
Use a real photograph when it builds trust, a diagram when it explains a process, and no image when it is only filling space. Resize an image to the largest size it will actually display, then export it in a modern format with a sensible quality setting.
Help browsers and people
Use responsive image sizes, lazy-load images below the first screen, reserve space to avoid layout shifts, and write alt text that describes the information a reader needs. Name files clearly for your own workflow, but do not expect filenames to replace page context.
A careful website build can make these choices part of the system instead of a last-minute cleanup.