Okay, this is good information; however, based on that the mod was most likely not installed correctly, as the presence of the random portrait button is the simplest sign that the mod has been installed. The fact that you can select portraits manually means that there is probably no issues on that side.
You have probably seen the install instructions I gave a few posts above this, please be sure that you have followed them carefully. I'll try to give a detailed list of things to verify.
On windows, there should be a file path "C:\Users\USERNAME\AppData\Roaming\Strive\mods\randomportraits\info.txt". If correct, the contents of that file will display on the right side of the panel when you hover the mouse over the mod name in the mod panel.
Press the "Active Mods" button on the mod panel. Near the top left corner of the mod panel, the text "Active Mod List" should appear as part of a transparent popup, with "randomportraits" underneath. (The visibility of this popup can be fixed by my bugfix patch on the Strive Discord, but it will not effect whether the mod works) If the mod is not listed, then try applying the mod.
In the folder containing game files, find and open the game file "Strive\files\scripts\mainmenu.gd" with any decent text editor. Find the line "globals.constructor.randomportrait(startSlave)", it should be just below the line "func _on_slaveconfirm_pressed():". If that line is not present, then the mod system did not add the mod to the game files. You may need to move the Strive game files to a new location or change the permissions of the folder to allow the game to change it's own files. A user once had an issue with permissions due to the game being located in the standard "Program Files" folder.
