It's perfectly possible to display images in list/tree view. Some js code has to be added to add this functionality.

I created a small module which does exactly this. The module has just one file which is relevant.

static/src/js/view_list.js:

openerp.listview_images = function(instance) { 

/* Add a new mapping to the registry for image fields */
instance.web.list.columns.add('field.image','instance.web.list.FieldBinaryImage');

/* Define a method similar to the one for forms to render image fields */
instance.web.list.FieldBinaryImage = instance.web.list.Column.extend({
/**
 * Return a image to the binary field of specified as widget image
 *
 * @private
 */
_format: function (row_data, options) {
        var placeholder = "/web/static/src/img/placeholder.png";
        var value = row_data[this.id].value;
        var img_url = placeholder;

        if (value && value.substr(0, 10).indexOf(' ') == -1) {
    /* Data inline */
    /* FIXME: can we get the mimetype from the data? */
    img_url = "data:image/png;base64," + value;
    } else {
    /* Data by URI (presumably slow) */
    img_url = instance.session.url('/web/binary/image', {model: options.model, field: this.id, id: options.id});
        }
    /* FIXME: move the 30px stuff to something templateable */
    return _.template('<image src="<%-src%>" width="30px" height="30px"/>', {
    src: img_url,
    });
}
});
}

The module is available on github, but I can't post link. [github.com / hsd / listview-images]