I cannot add any images to a new moodboard. I get stuck with a cross, and the images move but I can't fix them anywhere. If I click on the cross, the images disappear

I am trying to create a new moodboard.  When I add images from my device, they appear with a Cross in the corner.  I cannot fix them to the moodboard, they move with my cursor.  If I click the cursor, they disappear.  I have tried fit view to image but they are not there.