The best image is not simply the smallest file. It is the smallest file that still looks good at the size visitors actually see.
Resize before you compress
Uploading a 5000-pixel photograph into a 900-pixel website container wastes bandwidth. Resize close to the largest display size first, then compress the resized image.
Choose formats intentionally
JPEG remains practical for photographs. PNG is useful for transparency and certain graphics, but can be much larger. Modern formats such as WebP or AVIF can improve efficiency when your publishing workflow supports them.
Watch visual detail
Hair, fabric, gradients, text inside screenshots and product edges reveal compression problems quickly. Check these areas instead of relying only on the file-size number.
Optimize the most visible images first
Hero banners, product grids and blog thumbnails often account for a large share of transferred image data. Fixing a few heavily used assets can have more impact than processing every tiny icon.
Use responsive delivery
A mobile screen rarely needs the same image dimensions as a large desktop display. Responsive image markup or a good CMS image pipeline can serve more appropriate sizes.
Do not ignore layout stability
Specify image dimensions or aspect ratios so the browser can reserve space while the file loads. Faster downloads help performance, but stable layout matters too.
Use conventions your team can repeat, test the finished output, and document important decisions when the work affects customers, billing or reporting.