I'd like to be able to resize images on the client side before uploading them to the server. This would require some way to hook into the upload process.

I've tried Dropzone.onChange, but processing the images requires onChange to be an async handler, and it's currently not. i.e. If onChange returns a Promise, it would await that Promise before continuing on with the upload.

I've also tried the actionButtons / uploadButton with autoUpload = false. Using this prevents the automatic upload, and assigning an onClick handler to the uploadButton means I get to process the event, but I seem to have no way to initiate the upload once the processing is done. Is there a way to initiate the upload externally? That would solve the problem.