The subscription-based successor that ended the "CS" naming convention. 2. Why People Seek "Portable" Photoshop
The "CS7" name is likely a mix-up between two distinct eras of Photoshop: Portable Photoshop Cs7
Portable versions are unofficial, modified versions of the software designed to run without an installer. Photoshop CS6 vs 2021! - 28 Reasons to Upgrade The subscription-based successor that ended the "CS" naming
The last version with a perpetual license before the subscription model began. Photoshop CS6 vs 2021
Adobe transitioned from the "Creative Suite" (CS) branding to "Creative Cloud" (CC) after , which was released in May 2012. The version that would have been CS7 was instead released as Photoshop CC in June 2013.
The seventh major version, known for its speed and simplicity. It is often made "portable" because it is lightweight enough to run from a USB drive.
Finding information about "Portable Photoshop CS7" can be a bit tricky because as an official product from Adobe.