If you have added a lot of custom animations onto an image and wanted to change it to another image, you can easily do so in PowerPoint 2007 by right clicking on it. How about earlier versions of PowerPoint?
Here’s a workaround:
First of all, save the ppt as html. To do so, click File > Save as. Select Web Page under Save as
type. Once saved, exit PowerPoint.
Open the output folder, and look for the picture. Replace it with a new
picture that you want, and at the same time, ensure that the filename still
remain the same.
For example, if the filename is slide0001_image001.jpg, rename the new
picture as slide0001_image001.jpg and overwrite the original picture.
Now, open PowerPoint.
Click File > Open. Open the presentation (in .htm format) and resave it as