"decompressor are needed to see this picture"
The “… decompressor are needed to see this picture” problem often comes up for us when Mac created PowerPoint files are brought onto our PC based presentation setup.
A “quick and dirty” solution if you find yourself in this situation is to get the presentation back onto a mac. Copy out all affected pictures, paste them into “preview” ( File | new from clipboard), and export (or “save as”) JPEGs. Then put all your new JPEGS back into your presentation using the menu’s “insert picture” command. [the same process is even better if done in Photoship (if you have it at hand)]
To avoid this problem happening, when creating a PPT slideshow on a Mac use “insert picture” to place all your images and DO NOT use copy and paste.
Other tips that are said to help avoid this problem include:
-compressing pictures in a non-quicktime based app (e.g. photoshop).
-Allowing PowerPoint to compress or edit every picture (e.g. do a contrast adjustment to each pic in PP on the mac).
-use pictures converted into pdf files or png files rather than jpegs.
-avoid using tiffs and picts