$ sudo apt-get remove apng2gif 

Uninstall apng2gif including dependent package

If you would like to remove apng2gif and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove apng2gif 

Use Purging apng2gif

If you use with purge options to apng2gif package all the configuration and dependent packages will be removed.

$ sudo apt-get purge apng2gif 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove apng2gif 

See Also,