Just Player Heads

enablePlayerHeadCaching  default true
If enabled, enables the caching of player head textures. This fixes the limitations of the Mojang API, but does mean that whenever players update their skin the old head is still dropped until the server reboots or an administator uses the '/jph cache' command.

playerDropsHeadOnDeath  default true
If enabled, allows players to drop their head on death.

playerHeadDropChance  default 1.0, min 0.0001, max 1.0
Sets the chance of a player dropping their head if 'playerDropsHeadOnDeath' is enabled.

Texture values instead of generation via player-names
The mod uses texture values to generate the player heads. This means that there won't be any lag, which player-name generated heads usually cause.

Pure Vanilla Resources
Because the mod does not add any custom blocks, you may remove the mod and still have the heads previously gathered in-game.

In-game commands
If you want to generate a player head without any death event, you may do so via the jph command. Where the player name ignores capitalisation and the amount is optional (default amount is 1).
/jph head <playerName> (amount)

To empty the player head texture cache (if enabled in the config) you can reboot the server or use the following command:
/jph cache