gifs turn into pngs: PPT2002

[Lauri]

I've recently discovered that any gifs I place in Win
2000/PPT 2002 are converted to pngs after I close out the
file. I know this because if I place it and then do a Save
As Picture... it suggests saving it out as a gif. If I
close the file, reopen and do the same thing, it suggests
saving it as a png. My client always sends me bloated
files and I go through them, resaving the images at an
appropriate size and either gif or jpg. I've gotten files
that are 190 megs down to 27 megs doing this. Since pngs
tend to be unnecessarily large, I don't want them in my
files. Even if the png is now the same size as the gif, I
don't want to see it as a png and mistakenly think I have
to resave it again. How can I stop this from happening?

 

[Adam Crowley]

In actual fact a 256 colour (8-bit) PNG is usually smaller than a GIF (also
256 colour).
I know that doesn't help your recognition issue.
The way I understand it is that PowerPoint tends to convert all bitmaps that
aren't JPEGs into PNGs for the purposes of internal compression. 24-bit PNG
is a visually lossless compression format - the JPEGs that you save can be
much smaller and save masses of file size but suffer from lossy compression,
i.e. the picture quality is degraded.
That is just by way of explanation - I do exactly what you do myself and
only use PNGs for transparency as I don't think the file size is worth the
losslessness in most cases. In fact many images that are used in
presentations these days start out as JPEGs so it's a bit like recording VHS
quality video on a DVD...