Image projection

I have an ancient iBook G3/600 (Late 2001) with a mini VGA port and I want to give a presentation of images. How do I prepare my images on the computer and get them in the right order and size etc.
I have loaded the images to the laptop from my desktop via a memory stick, but when they appear on the laptop they have lost their thumbnails so they are incredibly difficult to select for the presentation.
Sorry for the dumb questions but I'm an old fashioned designer and maker of grandfather clocks and these technical things are a bit of a challenge! Old dogs, new tricks.