Create your own image collection.

Image collection is stored as a bitmap strip. Bitmap strip represents a set of images of small sizes which are located like a sequence of frames in a film.
Gather the images necessary to you and insert them, as frames, into single GIF- file. To create bitmap strip start operation File / Export and select file type bitmap strips. Now you can add this bitmap strip to prepared collections by means of the button Add in dialog Image Collections and use separate images from it for insertion to editing frames.