FrontendHaltPerformance·Intermediate·Conceptual·1 min read
Why does encoding an image at display size matter more than compression settings?
Short interview answer
Resolution scales bytes roughly with pixel count, so halving each dimension is about a 4x reduction — far larger than the difference between two reasonable quality settings. CSS scaling a large image down wastes bytes that were already downloaded and decoded.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.