Yes, I've been playing one version, then I updated it to another version (1.0.0.2).
Is there a problem? Because I see a propper readme file in this game file.
Mods
How to put mods (gfx) into my game?
Run the launcher.exe on your cs2d folder.
Select the mods tab.
Choose your mod.
Click run cs2d button.
If still not work,reinstall the cs2d.
Make sure dont put cs2d in the Program Files folder.
Kaotic Kaos: So; "Which cs2d that you're playing on?", "Which cs2d that you did put that skin into it?". Ask these questions yourself.
Kaotic Kaos: Regarding your image, you have not updated the Launcher.exe 
...\Counter-Strike 2D\gfx\weapons\
Mami Tomoe's steps, then just do it; change the background colour of the skin to magenta(255,0,255) for god sake!
Masea: I tested the link he provided and it is 25500255 I even tested it myself
Kaotic Kaos: This is very weird, make sure you did the right steps.