Q: powerpoint cannot access my photos

What app are the photos in?

What computer OS and version?

Just guessing, but this is a known issue with PowerPoint 2011 users who have upgraded to Yosemite or better, where iPhoto has been replaced by the Photos app. 2011 is hard-wired to point to iPhoto when you choose Insert>Photo>Picture Browser.

As workarounds, either:

• In Photos, select a photo, use File>Export to export the file, then in PowerPoint use the Insert>Picture>From File... command to import, or
• Drag the photo from Photos to your desktop, then from your desktop to PowerPoint.

If this doesn't answer your question, please consider posting at http://answers.microsoft.com/en-us/mac/forum/macpowerpoint where there are several PowerPoint for Mac expert users.

Try this:

Insert  >>  Photo  >>  Photo browser.

Selcet a photo library.

Select a photo, drag & drop to PowerPoint.