My Gallery (galaxy S4, android 5.0.1) contains old pjg files I created on my computer years ago. I have no idea how they got onto my phone and I cannot delete them. I am synced to upload photos to Dropbox but those pictures are not in Dropbox, or anywhere else in the clouds (Onedrive and Google Photos) or my computer. They are not photos from the camera. I am not sure if they are taking up room on my phone but I would like to remove them. I've tried syncing from the galaxy and from the clouds. I would appreciate any help.