I downloaded the png and placed it on the data but the plugin itself is not working I can't find it when I load it it's like it gets automatically unloaded

Make sure it's named "death.png" (or hit.png). The default one is 4KB, so try to make it a really small file. The default is 128 x 128 pixels, too.

How can i make a file smaller?

an image editor like paint.net