I am looking for a way that I can place a handful of mixed images (JPG) and videos (AVI?, MP4?) in a directory and loop through them continuously, in full screen, creating a slideshow from the images and playing the videos. I do require the ability to add and remove files from that directory, and have the outputting show reflecting the changes. Transition effects would be nice, but are not required. A little bit of Bash or Python scripting would be fine, but I would like to avoid a full custom software.
VLC does that. You can open a directory as media source through Media > Open Directory, all items in there will show up under the My Computer item. Select them all and click play; by default pictures are shown for 10 seconds.