Inserting and prezifying your slides is great, but be careful and look out for the following items and don't let them catch you out and ruin your lovely Prezi.
Because PowerPoint and Keynote don't have the functionality to zoom like Prezi does, they don't have to rely on such high resolution imagery. So long as the images on a slide look good enough when projected then that will normally work fine for the presentation.
Once these images are placed onto a Prezi canvas, you might decide that you want to zoom into them. If the quality isn't good enough, you could end up with the same pixilation problems we saw in Chapter 1, Best Practices with Imagery.
If you are worried about the quality of images once they have been inserted into your Prezi, just use the zoom feature and check for pixilation. If you lose quality and you know things just don't look good, then delete the image and use Prezi's Insert from web function to find a new image of better quality.