Crop Image

Resizing changes how many pixels an image has while keeping all of its content; cropping changes how much of the content is kept while leaving the remaining pixels at their original resolution. Confusing the two is a common source of disappointment — resizing a photo down does not remove the boring parts at the edges, and cropping a photo does not make a large file smaller in a way that follows any fixed size. They solve different problems and are often used together: crop first to the composition you want, then resize the cropped result if a specific output size is needed.

Most destinations a cropped photo is headed to have a fixed and non-negotiable aspect ratio, even when the platform itself does not advertise it clearly. A profile picture is displayed in a circular or square mask essentially everywhere, so anything other than a 1:1 source crop gets center-cropped again by whatever displays it, often cutting off the top of someone's head unpredictably. A video thumbnail lives on a 16:9 canvas; a printed 4×6 photo is a 3:2 ratio. Locking the crop selection to the ratio the destination actually expects means the framing you chose is the framing that ships, rather than something an external cropper decides for you afterwards.

A crop tool that worked by capturing whatever is rendered on screen would tie the output resolution to the size of your browser window, which is an accident of your current screen rather than a meaningful choice. Instead, the selection you drag is stored as a proportion of the full image — a rectangle from 20% to 60% of the width, for instance — and that proportion is applied to the original, full-resolution file when the crop is produced. A selection made on a 6000-pixel-wide photo, viewed at a scaled-down preview size on your screen, still produces a crop with full original resolution in the selected region.

Every other tool in this image category that accepts multiple files applies the same operation identically to each — the same compression setting, the same target dimensions, the same rotation. A crop is different in kind: the correct selection depends on where the subject sits within each individual photo, which varies from image to image even within a single batch. Applying one fixed rectangle across a batch of photos with different compositions would crop some of them correctly and cut a person's head off in others, with no way to know which in advance. Cropping stays a one-image-at-a-time operation for exactly this reason, and resizing — which is a uniform operation — is the tool for making many images the same size instead.