This aims to be somewhat standalone to run Photoshop from CS4 on Linux if you don't want to use GIMP.
Lutris
Lutris helps manage applications you install using wine. While Steam offers Proton as a "wine wrapper", Lutris is, in my opinion, more convenient for installing from a setup file. You can install Lutris from your package manager or from the software manager on the Linux distro of your choice (btw i use arch)
Within Lutris, you will want to make sure you have the proper wine version installed. This can be accessed by the hamburger icon in the top right, followed by preferences, runners, then scrolling down to wine. The icon to the right of the "settings" for wine lets you install a new version. I installed Adobe CS4 with wine-ge-8-26. After installing, set it as default in the wine settings in Lutris.
Install Adobe CS4
Download the setup files and extract them. You are looking for the Setup.exe file.
In Lutris, click on the + button in the top left, then select "Install a Windows game from an executable". Type in a game name ("adobe cs4" in my case) then select your installation directory. Afterwards, select the setup file by browsing to the Setup.exe file. The remainder of the installation takes place in the adobe installer, but if there are additional dependencies, do install them.
The Serial Code
1330-1679-3247-0265-6884-3635