Does anyone know of an app that lets you drag and drop images to create a slideshow? Not to create a DVD or video, but a slideshow you can control yourself. Office presentation tools is too complicated. It is also important that I can bring the slideshow with me easily from one machine to another.
I do not know of an application that will do exactly what you want.
What is available:
I know you didn't want to use a full office suite, but Open Office Impress is really the only application that can do all that you want. it isn't that hard to make a presentation of images. You can drag and drop images from the file manager into the current slide then resize the image to fit the slide. You can quickly create new slides by pressing Alt+I+E.
You can save this file and take it anywhere. If you don't want to require an office suite on other computers, you can export to a PDF file. You can then use the presentation function of the PDF viewer (F5). Once in presentation mode, use left click to navigate forward, right click to navigate backward, or Esc to exit.
In Ubuntu - using the Image Viewer (eog)*, you can just
For this to work, make sure the names of your images are correctly sorted in alphabetical order. You could, for example, name them 01.png, 02.png and so on.
You will also want to make sure the images have the correct aspect ratio for your screens.
As far as portability is concerned, you can just right click your Slideshow Directory and select "Compress" to create an archive, then take it with you on a USB Stick.
*: It will work the same way if you're using Shotwell.