Photo Resizer

Pre-Algebra · Axiom Academy

LESSON Resizing Photos & Aspect Ratio Why a photo looks right when you scale it one way and squished when you scale it another — it all comes down to one number. 1. Aspect Ratio: One Number for the Shape A photo's aspect ratio is just its width compared to its height. A 300 × 200 photo has ratio 300:200 , which reduces to 3:2 — three units across for every two down. Dividing kills the units and leaves a single number, 1.5 , that captures the photo's shape. Scale width AND height by the same factor k The k 's cancel — the ratio doesn't change Watch what happens when we enlarge the photo proportionally — multiplying both the width and the height by the same factor k . The frame gets bigger, but the ratio readout never budges from 3:2 . That kind of same-factor resize is a dilation : a true scaled copy. So what goes wrong when a photo looks squished? Someone scaled the width by one factor and the height by a different one. Now the cancellation breaks: , and unless k_w=k_h that extra factor warps the shape. Ratio preserved. The picture is a clean scaled copy — a dilation. The sun stays round. Stretched horizontally. Circles become ovals, the house looks fat, faces look wide. Squished horizontally. Everything looks thin and stretched upward. A circle that should be round becomes an ellipse — that's distortion you can spot instantly.

This is the written version of the interactive lesson above. See the full Pre-Algebra course.