I'd love it if anyone would make one of those cute, little #Gnome apps for making a slide show with full screen images:
Select a folder or specific image files, then drag and drop them to sort the order to show them in.
This is such a basic thing, if you ever hold a presentation showing pics from a trip or something, you need to make slides like this, but it's so time consuming in LibreOffice b/c you need to create a new page for each pic and then drag the pic to place it perfectly