A property management company wants to use images of the properties which it manages within its portfolio on its website and social media/marketing materials. They are just images of the building/block of flats or estate as a whole taken on public land not private. Does the company need to get permission from the owners to use these images?
Such images are almost certainly subject to copyright protection. (Unless the building, and the images, are old enough to be out of copyright, which is unlikely.)
They may not be reproduced or distributed without permission from th copyright holder. While the applicability of a "fair use" or "fair dealing" exception to copyright is always individual and fact-driven, the situation as described would be very unlikely to have such an exception apply. The use would be for a commercial purpose, would not be transformative, and would involve the whole image or a significant part of it.
Whether the images were taken on public land or private would not matter.
The management company would need to obtain permission from the copyright holder. This is likely to be the photographer, but might be someone else. If the images were released under a permissive license, such as a CC-BY license, that would constitute permission. But a license with a "share alike" clause, or a 'non-commercial" clause, would not constitute permission for that sort of use.
Beware of free image sites. Many images posted on such sites claim to be under permissive licenses, but are actually unauthorized, and the purported "license" is not worth the electrons used to transmit it.
It is probably safer for the management company to hire a photographer to take whatever pictures it wants to display on its site, or have one of its ordinary employees snap a cell-phone shot. Then proper permissions can be assured.