When inserting images into a Captivate project, you have two choices via the Insert menu: Image and Image Slide. Unfortunately for many new Captivate developers, the two commands are commonly confused, which can lead to a bit of stress during the development process.
For most developers looking to simply insert an image on a slide, choosing Insert > Image and then opening the desired image is a common process, one that doesn't need a great deal of afterthought.
However, if you accidentally choose Insert > Image Slide insead of Insert > Image, and open an image, the result is very different than simply inserting an image onto a slide. In fact, you will end up with a new slide in your project. The image that appears on the new Image Slide will be centered in the middle of the slide, just as you'd see if you inserted the image on an existing slide. But if you attempt to move the image, you'll quickly discover that you are unable to do so. What's the deal? In reality, you have actually merged the image into the slide background--sort of a two-for-one special that occurs automatically when you use the Image Slide command.
How easy is it to accidentally create a new slide instead of inserting an image onto an exisitng slide? Very easy! If you take a peek at Captivate's Insert menu you'll see that the Image Slide command is actually higher in the menu than the Image command (in fact, much higher).
And here is another way to create Image Slides: on your Library, drag an image from the Library to the slide's thumbnail on the Filmstrip. While you might expect the slide to gain the image, you'll instead end up with a new slide that contains the image (merged into the background). Had you dragged the image directly onto the slide, the image would have appeared on the slide as expected... but not merged into the background and therefore editable.
Am I saying that Image Slides are evil? Nope. Is the drag-and-drop to a Filmstrip thumbnail issue a bug? Nope. I'm saying that Image Slides are a feature... a feature you should learn to embrace... for stress sake.