already have the buffer

        IMAGE_FORMAT = "TIFF";

        obj.format = IMAGE_FORMAT;

        var arrayBuffer;

        var fileReader = new FileReader();

        fileReader.onload = function(event){

            arrayBuffer = event.target.result;

        // tiff.js which is limited in capabilities

        //var tiff = new Tiff({buffer: arrayBuffer});

        //var canvas = tiff.toCanvas();

        // UTIF.js

            var ifds = UTIF.decode(arrayBuffer);

            UTIF.decodeImage(arrayBuffer, ifds[0]);

        var ifds = UTIF.decode(imagedata);

        UTIF.decodeImage(imagedata, ifds[0]);

        if (ifds[0].t258==16){

            rgba_16bit = new Float32Array(ifds[0].data.filter((x,i) => i%2==0));

            rgba_16bit = rgba_16bit.map((x,i) => x + (ifds[0].data[2*i+1]<<8));

        //Elphel.Canvas.drawScaled($(canvas),cnv_display,settings.width);

        Elphel.Canvas.drawScaled(cnv_working,cnv_display,settings.width);

            delete this;

        }

        fileReader.readAsArrayBuffer(new Blob([imagedata]));

    }

    function process_image(imagedata){