I'm using OpenOffice.org Impress (the OpenOffice version of PowerPoint) to make a presentation that has a couple of graphics items in it. They are just two smallish GIF files that I wanted to insert into a slide. I used Insert > Graphics... then chose the files. They showed up fine but when I went on to finish out the presentation and came back to those slides that had the GIF's on them, they weren't there. All that was left of them was the box in which I inserted them along with the little graphics icon you often see on a web page when graphics don't load.

I checked the help files on Impress and it said that bitmaps can be inserted as graphics objects. So I changed these GIF's to BMP's using the gimp, and repeated the above process, with the same results.

Any ideas why my graphics aren't sticking?

There should be a toolbar at the bottom called the Options Bar. At the right hand end the fifth icon in (on my display) gives the option to toggle the display of graphics. Click on it and they should reappear.

I think this Options Bar may only show in edit slide mode or something. I do not have a presentation currently available to test it but you should be able to find it. Look in the View menu if necessary and click the Options toolbar to make it show.