I'm having trouble using Jcrop on responsive width images for the mobile version of a site.
When I apply a width setting of 100% to the uploaded image - to allow a user on a mobile device the best option of providing a successful crop, the outputted crop is not the crop area chosen.
This is due, I think, to jcrop working from the size of the true image, not the resized version (100% width), but I don't know how to fix it.
I have seen this question (and answer)but I don't understand how to apply to my Jcrop function:
$(function(){
    $('#target').Jcrop({
            aspectRatio: 4/3,
            bgColor:     '#000',
            bgOpacity:   .4,
            onSelect: updateCoords
        });
        });
        function updateCoords(c)
        {
            $('#x').val(c.x);
            $('#y').val(c.y);
            $('#w').val(c.w);
            $('#h').val(c.h);
        };
        function checkCoords()
        {
            if (parseInt($('#w').val())) return true;
            alert('Please select a crop region then press submit.');
            return false;
        };
This works beautifully if I don't apply any size CSS to the uploaded image, but as soon as I start trying to manage the images size for display, the cropped image is skewed.
I thought Google would have thrown up more results on this as i would expect it to be a common problem - or maybe I'm just too dim to see the obvious.
I hope someone can help.