In what situations do i need a property release for a photograph uploaded to my website? Is it if the photo generates revenue?

Your question is somewhat vague, but I will try to address it. You generally can use photos of buildings taken from a public street without permission. If you did not take the photo yourself, you will need permission from whoever owns the copyright to the image in question. Gereating revenue is not the only way that you can make a commercial use of someone else's intellectual property. So for example, if you were using the photo to decorate your business' website you would be making a commercial use of the image. Even if you posted it on your personal website without permission, it could still be copyright infringement, though the value of the claim would be minimal.

The revenue is irrelevant. You need a license if the copyright owner of the photo is not you. You do not need anything is the copyright of the photo has expired.

What do you mean by "a property release"? Whether the photo generates revenue does not matter. If the copyrights to the photograph belong to someone else, you need the owner's permission to post it on your website.

Revenue generation is irrelevant. You cannot upload and display a photograph on your web-site without getting permission from the copyright owner. If you upload and display a photograph without permission, you are engaging in copyright infringement, which could lead to statutory damages of $750 to $35,000 for each such photograph, and statutory damages of up to $150,000 if your infringement is found to be "willful", Note that copyright infringement is a strict liability offense---ignorance of the law is no excuse. The photographer generally owns the copyright in his pictures, unless he licenses it or assigns it to someone else, or unless he creates the photograph as a work for hire for some other person or entity. More generally, if you do not understand this basic and simple concept of copyright law, then I suspect you are making many even more serious legal errors in operating your website. Anyone who operates a web-site for profit or promotional purposes should retain and consult with legal counsel, You would be quite surprised at how often persons in your situation find themselves in the middle of very expensive and sometimes financially disastrous litigation because they did not invest the modest sum necessary to work with intellectual property counsel. Anyone who operates a web-site faces a myriad of rather complex and sophisticated intellectual property law issues, and it is a risky business indeed to fail to work closely with IP counsel.