Definitely your PowerPoint file is corrupted now. It is corrupted because of that photo you had added from Internet. Have you tried to open your file in “PowerPoint 2003 Viewer” ? If No, then try these methods to recover it.

1: Open the presentation in MS Office Word- Open word, go to the File menu and click Open. In the open dialog box, click the arrow next to the Files of Type box at the bottom of that dialog box, and then click Recover Text From Any File. Now Navigate to your corrupt file, select it, and then click Open.

2: Use Safe Mode- You should try to open your file in safe mode.

3: Try a third Party Recovery Tool- You can try some softwares to recovery your corrupted file. Like..
SysInfoTools MS Powerpoint Pptx – Free
S2 Recovery – Free
Stellar Phoenix PowerPoint Repair – Paid (One time Payment & Lifetime License)