Scenario: You take a 12MP photo with your phone camera.

Uncompressed RAW: 36 MB (12 million pixels × 3 bytes)
PNG (lossless): ~18 MB (50% compression - some redundancy removed)
JPEG high quality: ~3 MB (92% compression - barely noticeable loss)
JPEG medium quality: ~800 KB (98% compression - slight artifacts)
JPEG low quality: ~200 KB (99.4% compression - visible blocks)

For Instagram/Facebook: JPEG medium (800 KB) is perfect - 45× smaller, looks great on phones!

For photo printing: JPEG high (3 MB) or PNG (18 MB) - need quality for large prints

This deep dive covers Real-World Example: Photo Sharing within Compression for GCSE Computer Science. Revise Compression in 3.3 Data Representation for GCSE Computer Science with 16 exam-style questions and 16 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 12 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Practice questions for Compression

Which statement correctly describes lossy compression?

A. The original file can be perfectly restored after decompression.
B. Data is permanently removed and the original cannot be exactly recreated.
C. The compressed file is always the same size as the original.
D. No data is removed during the compression process.

1 markfoundation

Explain how run-length encoding (RLE) works to compress data.

3 marksstandard

Real-World Example: Photo Sharing

Practice questions for Compression

Quick recall flashcards

16 questions on Compression: practise free