Passing custom parameters while uploading an image — is this a safe hack?

I need to add some custom data to upload request in Upload image dialog.

At the moment I've came up with a solution that looks more like a hack:

in plugins/image/dialogs/image.js I extended Upload tab

    {
    type: 'fileButton',
    id: 'uploadButton',
    filebrowser: {
        target: 'info:txtUrl',
        action: 'QuickUpload',
        params: { insert_thumbnail: true }
    },
    label: editor.lang.image.btnUpload,
    'for': [ 'Upload', 'upload' ]
},
    {
    type: 'checkbox',
    id: 'insertThumb',
    label: 'Insert as thumbnail',
    'default': 'checked',
    onChange: function() {
        var form = this.getDialog().getContentElement( 'Upload', 'upload' ).getInputElement().getParent().$;
        form.action = form.action.replace( /insert_thumbnail=[^&]+/, 'insert_thumbnail=' + this.getValue() );
    }
}
]

Is there a more elegant way to get this done?