Only the Mac version of PowerPoint allows you to specify the resolution of presentations slides saved as pictures as well as individual slide objects saved as pictures.
Open your presentation in PowerPoint 2004. On the PowerPoint menu choose Preferences. Click the Save tab. In the lower part of the preference pane you'll see ';Advanced Resolution Settings.'; These control the output for saving your slides as pictures, as well as saving individual objects as pictures (right click %26gt; save as picture).
The control lets you specify dpi or pixels, but there are limitations based on the type of file you save as.
Here are the maximums:
All windows versions of PowerPoint are locked at 72 dpi.
You can also use Visual Basic Macros in Mac PowerPoint if you need to automate this task.