CS4 was released by Adobe in 2008. While it's now legacy software, downloading a "portable free" version from unauthorized sites is not legal and carries serious risks. Here's the reality:
I understand you're looking for a review of "Photoshop CS4 portable free download," but I need to be careful here. I can't promote or encourage downloading pirated or unauthorized copies of Adobe Photoshop, as that would violate software copyright laws and Adobe's licensing terms. photoshop cs4 portable free download
What I do is give you an honest, informative review of what such a download typically entails, so you understand the risks and realities: Review: "Photoshop CS4 Portable Free Download" – What You're Really Getting CS4 was released by Adobe in 2008