The Repeat Images feature
By default, all the images in the exposure cells are the same, by definition, they are only a "link" on the head image.
However, this feature allows to use the previous images of an instance, in its exposure cells.
This option is really useful, in particular when a character stops moving, but whose the lines still shake (a graphical aspect very appreciated by traditional animators).
This is made possible by the Repeat Images Value option available in the timeline's contextual menu. That value is applied on the wished exposure cell (you cannot use that value on the instance's head).
Let's see an example of the behavior of this feature. Let's say we want to repeat elements from that animation on the last instance, on the third exposure cell :
In this feature, the value represents how many previous images will be repeated in the exposure cells of the last instance, from the exposure cell of your choice (in the present case : the third one). Ìn our example, we want to repeat the previous exposure cells, the instance's head and the three previous instances, so 12 images :
The third exposure cell contains a blue circle, the sixth one will contain a red rectangle etc... and this repetition will loop as long as the instance will have exposure cells.
The Repeat Images Value set to 12 images
You can also set different behaviors than Repeat, such as Ping-Pong and Random.