Steps to reproduce the problem, first try:

1- Open both, an empty Writer document and your file browser on a folder containing images.

2- Select several images from that folder and drag-n-drop them into the Writer document all together on one movement

Result: even if the "Image" frame style is set with "no wrap" by default and even if all the images have the Wrap property set to "no wrap", all images pile up on the same position and there is no easy way to separate them. 

Second try. 

1- On an empty Writer document insert a couple of empty line breaks.

2- Again drag-n-drop several images all together on one movement, but being careful of using the last paragraph as "drop target"

Result: as before, the images pile up on the same point, but if you select one of them and press the up arrow a couple of times, all the other images on the pile will be pushed below the selected image. 

NOTE 1: this separation do not occur if you push the image downwards

NOTE 2: on the first try if you push one image upwards the images do NOT separate.