Remove tooltips from PDFs exported from PowerPoint
I found a workaround here.
To summarize:
The tooltips are included for accessibility.
To turn them off, change the options in the Save as PDF... dialog and disable "Document structure tags for accessibility"
That tooptip is generated from the Alt Text in Word. By default, it is the image file name/path you copied and pasted. It can be modified in Word or PowerPoint, as described here.
To remove it, you have 3 solutions:
In Word or PowerPoint, use File -> Print. This will remove all Alt Text.
In Word or PowerPoint's Acrobat ribbon, choose Preferences, then uncheck “Enable accessibility…" Sorry for not having an English version.
Using acrobat.In Acrobat 9, go to Advanced > PDF Optimizer. (The path may be slightly different in Acrobat 8.) Under Discard Objects, make sure that Discard Document Tags is checked. This will remove alt text from images. You can also run this in batch (on multiple PDFs at once) by going to Advanced > Document Processing > Batch Processing. Decribed here.