When you override the property you can define custom animation by providing an array containing at least two objects and an optional . The first object describes the start and and the second contains the final state. Attention: you can't animate complex, non numeric css properties. If you want to animate e.g. the transform property you have to define the first object with the initial state and the second with optional end points. The step function sets the css for each frame manual.

Option	Description	Default	Values
url	Overrides the url in the data-postify attribute	undefined	custom string
animation	Choose one of the predefined animations or declare a custom one	fade	fade slideUp slideDown slideLeft slideRight flip scale custom animation: [{{..}, {..}, optional: function(now, fx)}]
duration	Defines the duration of all animations	Slow	Fast, slow, amount of ms
delay	The delay of the image loading in ms	0ms	amount of ms
priority	Loads pictures in a certain order	0	all numbers >= 0
showLoading	Defines whether a loading animation should be displayed or not	true	true, false
loadingClass	The class of the surrounding loading animation	postify-loading	custom class name
loadingElements	When your loading animation needs more items they can be added here	<div></div><div></div><div></div><div></div>	custom html string
adjustSize	How should the postloaded image adjust the size itself or the size of the containing element. parent: adjust the size of the parent so it matches the size of the image. cover: Scale the image, that it fills the parent. childHeight: Force the child to adjust its height by parent. childWidth: Force the child to adjust its width by parent. auto: choose automaticly how to adjust the size of the image that it fits the parent.	parent	parent, cover, childHeight, childWidth, auto