How does PPT Mac store graphics internally?
Vector graphics are generally stored as PICT version 2.
Copy and Paste Special of vector data "As Picture", is stored internally in PICT format.
If a PPT/Windows file contains WMF or EMF graphics, the graphics are duplicated to an additional
PICT. The file then includes a metafile and a PICT.
If you change the embedded metafile (ie, by updating a char) the metafile is discarded. The the Windows version can convert the remaining PICT back to metafile, so there's no need to update and save both formats.
Raster graphics other than JPG, GIF or BMP are converted to PNG and stored internally as PNG.
JPG/GIF/BMPs that have effects applied (like red-eye reduction) are converted internally to PNG.
PS files are converted internally to a PICT. The EPS preview, if any, is displayed, but the EPS code is stored as a comment in the PICT. When printed to a PS printer, the EPS code in the comment executes and we don't print the preview. When printed to a non-PS printer, you get the preview picture.
The Win Office PICT to WMF filter recognizes the EPS comment embedded in the PICT, and preserves it when translating to a metafile. So on win office, the same thing happens. The EPS code prints to PS printers only.