PR photography is a general term describing photos taken for press releases. PR photos come in all forms and styles.
The photos can be a mix of corporate event photography, business portrait photography or a combination of them both (portraits taken at events). The photos are used by marketing teams to send out to professional and local press and go together with press releases.
Geared more towards the public, rather than trade publication and readership. PR photography can cover anything from red carpet events, portrait, at-work photos, celebrity endorsements photography and more.
PR photo need to communicate a story to the viewer, in a simple and easy to understand way. A good PR photo is also one the editors are keen to publish. Having good PR photos can help your press releases get published and sway editors to run your story. There's more than one way to do this, but the photo has to be something that publications will be happy to show on their pages.