As with many things in layout, there are a number of ways to treat images in InDesign. But some methods are better than others when it comes to creating ebooks. The most important pieces are paying attention to text threads, and using object styles.
If you have pages, chapters, or even a whole book which is threaded from front to back, it’s important to consider anchoring the images to the text. Not doing so means that the images will come out after the text thread in the ebook; this might mean, for example, that chapters 1-10 are in the ebook and then there is a traffic jam of pictures at the end of chapter 10, instead of sprinkled throughout as the design intended.