1. Set a file-size target before you begin
Define a clear budget for each context. Product galleries and blog thumbnails should not use the same maximum size.
2. Resize dimensions first, then compress
Large source dimensions force extra bytes. Match width and height to the real display size before quality tuning.
3. Pick the right format per image type
Use JPEG for photos, PNG for transparency-critical assets, and WebP for modern balanced delivery.
4. Tune quality with visual checkpoints
Decrease quality in small steps and compare edges, skin tones, and gradients on both light and dark backgrounds.
5. Strip unnecessary metadata
Removing EXIF and non-essential metadata can reduce file size and improve privacy for shared assets.
6. Validate output in real loading conditions
Test pages on mobile network throttling and confirm that image decoding does not block meaningful content rendering.
Compression checklist
- Dimensions match real layout slots.
- Format selected by image type and browser support.
- Quality tuned by side-by-side visual review.
- Metadata cleaned before publish.
- Final page tested on mobile speed profile.