code: function setInitialDimensions(el) {
  	    if (el.holderData) {
  	        var dimensions = dimensionCheck(el);
  	        if (dimensions) {
  	            var flags = el.holderData.flags;
  
  	            var fluidConfig = {
  	                fluidHeight: flags.dimensions.height.slice(-1) == '%',
  	                fluidWidth: flags.dimensions.width.slice(-1) == '%',
  	                mode: null,
  	                initialDimensions: dimensions
  	            };
  
  	            if (fluidConfig.fluidWidth && !fluidConfig.fluidHeight) {
  	                fluidConfig.mode = 'width';
  	                fluidConfig.ratio = fluidConfig.initialDimensions.width / parseFloat(flags.dimensions.height);
  	            } else if (!fluidConfig.fluidWidth && fluidConfig.fluidHeight) {
  	                fluidConfig.mode = 'height';
  	                fluidConfig.ratio = parseFloat(flags.dimensions.width) / fluidConfig.initialDimensions.height;
  	            }
  
  	            el.holderData.fluidConfig = fluidConfig;
  	        } else {
  	            setInvisible(el);
  	        }
  	    }
  	}
docs: Sets up aspect ratio metadata for fluid placeholders, in order to preserve proportions when resizing
  
  @private
  @param el Image DOM element