Quicktime and a TIFF (uncompressed) decompressor are need to see this picture
You may see this message where images should appear when attempting to show on your PC a PowerPoint presentation that has been created on a Mac. It may well apply to file formats other than TIFFs. It seems that on Macs images are compressed using Quicktime, and as discussed elswhere, quicktime does not always work on PC presentations. It would appear that this occurs if pictures are copied and pasted directly from web pages into PowerPoint, rather than being saved to the computer and then inserted into PowerPoint. So what can you do?
 

To ensure the best images quality, find the original pictures,and reinsert them on a PC, or try converting the images to JPEGs. Of course in practice the originals are elsewhere. If you have access to a Mac the following might work. Open the PowerPoint on the Mac, and make sure you can see all the images. Then go to "file" and then "save as", and select the "web page" option. This will save a web version of the presentation in a new folder. This folder now contains a large number of files in various html and image formats. Copy this folder and the original PowerPoint on to a PC.

You now need to explore these files. It's quite confusing as there are lots of files with similar names. (in windows explorer selecting "sort by type" will make it easier to see what is going on). Look for a GIF file with a file name corresponding to the slide number. Just to add to the confusion there may well be more than one GIF with each slide numebr. Ignore the very small files (eg 1KB) and look for larger files eg. "slide 0016.gif 125KB" This file is a gif picture of that entire slide, including text. So now you can start a new PowerPoint presentation on your PC, and insert these images in the usual way.

Copying and pasting pictures from web pages into PowerPoint ,may also generate a security warning with PowerPoint 2007 so beware!