Thank you for asking. In addition to @VasT reply i am replying for your query.
The guidelines shared with you say: Only share photos you have taken yourself or received permission to use directly from the copyright owner.Do not download and post photos from Google Search, Google Maps, social media, stock photo websites, or elsewhere on the internet without receiving permission from the owner of that photo. It means that you should be able to demonstrate that you have received the permission.
The best solution is to post only your own photos.
You may even use Google Connects Gallery if you don’t have your own picture.
From the link above (again, please read directly from the link, I am just attaching below for providing a short partial answer)
"> Only share photos you have taken yourself or received permission to use directly from the copyright owner. Do not download and post photos from Google Search, Google Maps, social media, stock photo websites, or elsewhere on the internet without receiving permission from the owner of that photo. > Make use of our photo library to illustrate your post if you don’t have your own images. All photos there are approved, rights-cleared, and licensed by Google for use within Local Guides Connect only. > Give credit in the caption for images you have permission to use. In the photo caption, write, “(Courtesy of ‘Copyright Holder’s Name’).”
You already got the answer from @VinayKrishna and to add on that, please refer to this post on Uploading a photo on Connect? Read these guidelines first, I am sure this will help you understand better, we also have another tips based on Google Maps photos stated as What photos should I share on Google Maps?. Photos are more like a property, is either you use your own property that you manufactured yourself, buy your own or borrow from someone and with permission that is when you can use it, if you did not get permission is more like you have stolen the property. Legal actions may be taken against you. Cheers!
In my opinion, if you don’t have original photos, you could use photos from Connect’s Photo Library to illustrate the story you’re gonna share. Here’s the link: How do I use the Connect Photo Library