Activity
Adjust the quality slider or use the quick buttons. Compare the compressed image to the original and explain what changes you notice.
Click on the image to pick a detail area; the zoom panels show the difference more clearly.
Quality Control
Original (100%)
Compressed
Zoom (Original)
Zoom (Compressed)
Lossy Compression – Questions
Answer the questions, then select Check answers. Use Download PDF to save your work.
1. What happens to image quality as lossy compression increases?
Quality decreases: fine detail and colour accuracy are lost as data is discarded.
2. Name one advantage of lossy compression.
Smaller file size, so images load faster and use less storage/bandwidth.
3. Why can’t you perfectly restore a lossy-compressed image?
Data has been permanently removed, so the exact original information is lost.
4. Give one example of when lossy compression is acceptable.
Web photos or social media images where small file size is more important than perfect quality.