PowerPoint 2016 - No "publish slides" option

[twinbytes]

In an effort to figure out what slides are the culprit in a massive 300 slides PowerPoint presentation, we found instructions as linked below to save the slides to a library.  However, When following the instructions, there is no such option to "Publish Slides".  Does anyone know why this feature may not exist?  Alternatively maybe you have another solution how we can find which is the largest slide which is what we really are trying to find out?

https://www.dummies.com/software/microsoft-office/powerpoint/how-to-save-slides-to-a-library-in-powerpoint-2016/

Thanks in advance.