An aspect ratio compares width with height; it does not state a resolution. A 1:1 crop can be 300×300 or 1200×1200. A 16:9 crop can be 1280×720 or 640×360. CropFrame locks the shape while leaving the actual source-pixel rectangle visible.
What the common presets mean
1:1 is square. 4:3 and 3:2 are common landscape photo shapes; 16:9 is wider; 9:16 is its portrait counterpart. These names describe geometry only. A destination may impose its own minimum pixels, safe areas or compression, so check that destination separately.
Pixels require integer rounding
Many source sizes cannot express a ratio perfectly with integer sides. For example, 1000÷16×9 is 562.5. A cropper must choose 562 or 563 pixels; CropFrame rounds deterministically and keeps the difference within one source pixel. The displayed width and height are the authoritative result.
Keep the crop in its proper scope
CropFrame creates a new Canvas-decoded image and does not preserve metadata, provenance, measurements or evidentiary fidelity. Use it for ordinary digital publishing and design. Do not use it to prepare identity, medical, legal, inspection, emergency, navigation or other safety-critical imagery, and independently verify every important result.