New in 5.2: a standalone aspectRatio validator (independent from the image editor).
Accepts '16:9', [16,9], a decimal ratio, or a function
(w,h) => boolean | string. Tolerance defaults to 1% and is tunable with
aspectRatioTolerance.
What you should see: images outside the required aspect ratio are rejected at selection time, before any upload.
This demo accepts only 16:9 images (within 1% tolerance).
AjaxUploader.create('#uploader', {
uploadUrl: '/ajaxupload.axd/upload',
accept: 'image/*',
aspectRatio: '16:9', // also: [16,9], 1.7777, (w,h) => ...
aspectRatioTolerance: 0.01 // 1% default
});