Pixel dimensions
Dimensions describe width and height in pixels. Oversized images use more data and can slow page loading.
File size
Two images with identical dimensions can have very different file sizes because of format, detail and compression.
Visual quality
Quality should be judged in the context where the image will appear.
A practical workflow
- Decide the displayed dimensions.
- Resize while preserving aspect ratio.
- Choose an appropriate format.
- Compress and preview.
- Check desktop and mobile.