The image gallery view has the capabilities of viewing the captured images or documents, selecting some of the images or documents, sorting them etc.
If you want to sort the images or documents in the image gallery view, call enterManualSortMode().
Under the sort mode, you can long press on an image to move it a place you want it to be.
In order to enable the multi-select function, you can call enterSelectMode().
Under the Select mode, you can make the image selected by clicking it.