I think the issue you are experiencing has to do with a file sharing site that you have used. Try bypassing that. We can use the shortcut of save as and see what happens. When you have your presentation open press F12. This will open Save As. Select the image type like jpg in the file type dropdown and then select the directory you want to save it. Give it a name then hit save. A small window will appear asking if you want to save all slides or just the one. It will make a folder with all the slides if you choose all. Let me know if that works. Personally I hate using File and then save. I have always used F12 to get right to saving something. Works on all MS Office products.