Using PowerPoint 2002:
Just increase the size of the slide. The DPI "magic number" seems to be locked into 72 dpi, but by increasing the size the saved image dimensions stay the same.
Found this and much info here: http://www.pptfaq.com/FAQ00052.htm
This says:
Exporting from PowerPoint to other file types
To export your PowerPoint slides to other file types (BMP, WMF, JPG, PNG, etc)
Open your presentation and choose Save As from the File menu.
In the Save As Type dropdown listbox, choose the file type you want to save.
Give the file a name and click OK.
PowerPoint asks whether you want to export just the current slide or your entire presentation. The question is worded a little oddly, so read the message carefully before clicking Yes or No.
Increase the resolution/quality of bitmaps from PowerPoint
The RnR PPTools Image Exporter add-in for PowerPoint gives you complete control over the resolution, destination, filenames and format of bitmaps you export from PowerPoint. It also gives you better quality images than you can get from PowerPoint in most cases.
Increase the resolution of your exported bitmaps without an add-in
When PowerPoint exports bitmap files, it uses the current Slide Page Size to determine the resolution (ie, number of pixels) in the files it makes. Here's the formula:
Image-width-In-Pixels = Slide-width-In-Inches x Magic-DPI-Number
What's the Magic-DPI-Number? That depends on the version of PowerPoint and (in PowerPoint 97 your video driver settings as well).
Here are a few rules of thumb in case you don't have access to the system you're supporting:
For PPT97, the Magic DPI Number is 96 if your video is set to Small Fonts, 120 if Large Fonts.
For PPT 2000 and 2002, the Magic DPI Number is 72.
For PPT 2003, the Magic DPI Number seems to wander from 80 to 96, perhaps depending on the service pack you have installed. But you can change that: See HOW TO: Change the Resolution of a PowerPoint Slide That You Export As a Picture
For PowerPoint 2007, the Magic Number is back to 96, 120 or whatever your Windows video display resolution is set to. But for PowerPoint 2007 with Service Pack 1, if you use the registry setting above, you'll get higher resoluton images, but they'll be corrupted. Don't bother.
That's the default -- how to change it?
To get higher resolution but bitmap exports, choose File, Page Setup (or File, Slide Setup) and increase the size of your Slide page. Keep the new size proportional to the old, please, or you'll distort your graphics, set text boxes to wandering randomly around the page and so on. We don't want that.
OR ... if you have PowerPoint 2003/2007 and have read the link above, you can fiddle with the registry each time you want to change resolutions. Not recommended for the faint of heart. Or anyone else.
The Microsoft knowledge base article on the registry mod is here: http://support.microsoft.com/kb/827745
Didn't try it as I didn't have PP 2003 or 2007
