For anyone who has had to generate an image in PowerPoint, with a specific pixel density, the rule of thumb is 95 pixels per inch. There is no way to set this, though, and with the lossy jpg format, you can end up with a much lower image density than you wanted.
I recently had to submit a jpg image of at least 1400 x 1400 pixels, using PowerPoint. There is a fairly lame add-on that costs $40 - looked like the aspect ratio remained locked. But the cheaper, easier way to do this, without writing macros, is to set your page measurement for 95 pixels per inch, so for my minimum 1400 x 1400 pixel image, I set the page for 16 inches x 16 inches, *before* creating the image (if you do it afterwards, your stuff will be distorted). Since I am not printing, the print size doesn't matter. Then when the slide was saved as a jpg, the image density was 1536 x 1536 pixels. A mouse over the file name, in Explorer, provides the pixel density. I know this is technical, but I really had to dig to figure this out, and thought it was worth sharing.
