The best image size for a website depends on placement, not on a single universal number. A homepage hero, an inline article image, and a small card thumbnail each need different dimensions and file-weight targets.
Match the image to the layout role
Hero images often need wide proportions and larger dimensions than a blog thumbnail. Inline article images usually do not need the same width as a full-screen banner. Before exporting anything, decide where the image will appear and how large it really needs to be in the layout.
Responsive design still rewards sensible source sizes
Browsers can scale a huge image down visually, but they still download the original bytes. That is why right-sizing a file with Image Resizer can matter just as much as compression. Fewer unnecessary pixels usually means a lighter page and a cleaner editing workflow.
Plan for common use cases
Square social graphics, vertical story layouts, and wide thumbnail crops all benefit from predictable aspect ratios. A small preset library makes repeated publishing work faster because you do not have to remember the same numbers each time.
Use compression after the dimensions are correct
Once the image matches the layout, run it through Image Compressor or a dedicated converter if a different output format makes sense. Compression is easier to judge when the pixel dimensions are already close to the final display size.
Leave room for context-specific judgment
There is no fixed width that works for every site, every theme, or every content block. Build a small set of practical targets for your own layout system, then keep testing with real pages instead of relying only on generic advice.