Girls

Put the spray .wad file into your game folder cstrike (in localized versions the active folder might be cstrike_russian). After that, start the game and go to Options → Multiplayer → Customize to pick the Girls spray from the list. If the new spray doesn't show up, restart CS 1.6 so it rescans the folder.

Spray files go in cstrike. The spray you're currently using is saved there as tempdecal.wad. Don't put sprays in cstrike/maps or cstrike/sprites - those folders are meant for maps and sprites, not spray logos.

1. Go to Options → Multiplayer → Customize.
2. Pick the Girls graffiti in the spray list and confirm.
3. Check that a key is assigned to Spray logo in Options → Keyboard.

Then just press that key while facing a wall in game.

Typical reasons: the file isn't in cstrike, or it's not a valid spray .wad file. Check the console settings cl_allowupload 1 and cl_allowdownload 1, and ensure r_decals isn't set to 0, as that turns off decals and sprays.

Go to Options → Multiplayer → Customize and choose a different spray from the list, or select the default logo to return to the standard one. For a full reset, delete cstrike/tempdecal.wad - the game will then create a fresh default spray file.

They do work, but the server controls how. If the server runs with sv_allowupload 0, your Girls graffiti isn't sent to other players, and you'll typically only see it on your own screen. When uploads and downloads are enabled, the spray gets sent to other clients.

Usually the server blocks spray uploads with sv_allowupload 0, or consistency checks swap out custom files. Another player might also have cl_allowdownload 0, so they never get sprays. On those servers, only the standard spray remains visible.