diff --git a/plugins/minimize_size/__init__.py b/plugins/minimize_size/__init__.py
index dd6500e..d49b551 100644
--- a/plugins/minimize_size/__init__.py
+++ b/plugins/minimize_size/__init__.py
@@ -1,10 +1,27 @@
 import tasks
 
 
+def validate_manifest(data, validator, error):
+	import os.path
+	schema_path = os.path.join(os.path.dirname(__file__), 'manifest-schema.json')
+	validator(data, schema_path)
+	if 'zerofree' in data['plugins']['minimize_size']:
+		zerofree_schema_path = os.path.join(os.path.dirname(__file__), 'manifest-schema-zerofree.json')
+		validator(data, zerofree_schema_path)
+	if data['plugins']['minimize_size'].get('shrink', False) and data['volume']['backing'] != 'vmdk':
+		error('Can only shrink vmdk images', ['plugins', 'minimize_size', 'shrink'])
+
+
 def resolve_tasks(taskset, manifest):
 	taskset.update([tasks.AddFolderMounts,
 	                tasks.RemoveFolderMounts,
 	                ])
+	if 'zerofree' in manifest.plugins['minimize_size']:
+		taskset.add(tasks.CheckZerofreePath)
+		taskset.add(tasks.Zerofree)
+	if manifest.plugins['minimize_size'].get('shrink', False):
+		taskset.add(tasks.CheckVMWareDMCommand)
+		taskset.add(tasks.ShrinkVolume)
 
 
 def resolve_rollback_tasks(taskset, manifest, counter_task):
diff --git a/plugins/minimize_size/manifest-schema-zerofree.json b/plugins/minimize_size/manifest-schema-zerofree.json
new file mode 100644
index 0000000..bd6715d
--- /dev/null
+++ b/plugins/minimize_size/manifest-schema-zerofree.json
@@ -0,0 +1,18 @@
+{
+	"$schema": "http://json-schema.org/draft-04/schema#",
+	"title": "Minimize size plugin manifest",
+	"type": "object",
+	"properties": {
+		"volume": {
+			"type": "object",
+			"properties": {
+				"partitions": {
+					"type": "object",
+					"properties": {
+						"type": { "enum": ["none"] }
+					}
+				}
+			}
+		}
+	}
+}
diff --git a/plugins/minimize_size/manifest-schema.json b/plugins/minimize_size/manifest-schema.json
new file mode 100644
index 0000000..0d7942c
--- /dev/null
+++ b/plugins/minimize_size/manifest-schema.json
@@ -0,0 +1,25 @@
+{
+	"$schema": "http://json-schema.org/draft-04/schema#",
+	"title": "Minimize size plugin manifest",
+	"type": "object",
+	"properties": {
+		"plugins": {
+			"type": "object",
+			"properties": {
+				"minimize_size": {
+					"type": "object",
+					"properties": {
+						"shrink": { "type": "boolean" },
+						"zerofree": { "$ref": "#/definitions/absolute_path" }
+					}
+				}
+			}
+		}
+	},
+	"definitions": {
+		"absolute_path": {
+			"type":    "string",
+			"pattern": "^/[^\\0]+$"
+		}
+	}
+}
diff --git a/plugins/minimize_size/tasks.py b/plugins/minimize_size/tasks.py
index 96bfdf2..37798ae 100644
--- a/plugins/minimize_size/tasks.py
+++ b/plugins/minimize_size/tasks.py
@@ -1,7 +1,10 @@
 from base import Task
 from common import phases
-from common.tasks import bootstrap
 from common.tasks import apt
+from common.tasks import bootstrap
+from common.tasks import filesystem
+from common.tasks import partitioning
+from common.tasks import volume
 import os
 
 folders = ['tmp', 'var/lib/apt/lists']
@@ -41,3 +44,58 @@ class RemoveFolderMounts(Task):
 
 		os.rmdir(info.minimize_size_folder)
 		del info.minimize_size_folder
+
+
+class CheckZerofreePath(Task):
+	description = 'Checking path to zerofree tool'
+	phase = phases.preparation
+
+	@classmethod
+	def run(cls, info):
+		from common.exceptions import TaskError
+		import os
+		zerofree = info.manifest.plugins['minimize_size']['zerofree']
+		if not os.path.isfile(zerofree):
+			raise TaskError('The path `{path}\' does not exist or is not a file'.format(path=zerofree))
+		if not os.access(zerofree, os.X_OK):
+			raise TaskError('The path `{path}\' is not executable'.format(path=zerofree))
+
+
+# Get zerofree here: http://intgat.tigress.co.uk/rmy/uml/index.html
+class Zerofree(Task):
+	description = 'Zeroing unused blocks on the volume'
+	phase = phases.volume_unmounting
+	predecessors = [filesystem.UnmountRoot, partitioning.UnmapPartitions]
+	successors = [volume.Detach]
+
+	@classmethod
+	def run(cls, info):
+		from common.tools import log_check_call
+		zerofree = info.manifest.plugins['minimize_size']['zerofree']
+		log_check_call([zerofree, info.volume.device_path])
+
+
+class CheckVMWareDMCommand(Task):
+	description = 'Checking path to vmware-vdiskmanager tool'
+	phase = phases.preparation
+
+	@classmethod
+	def run(cls, info):
+		from common.exceptions import TaskError
+		import os
+		vdiskmngr = '/usr/bin/vmware-vdiskmanager'
+		if not os.path.isfile(vdiskmngr):
+			raise TaskError('Unable to find vmware-vdiskmanager at `{path}\''.format(path=vdiskmngr))
+		if not os.access(vdiskmngr, os.X_OK):
+			raise TaskError('vmware-vdiskmanager at `{path}\' is not executable'.format(path=vdiskmngr))
+
+
+class ShrinkVolume(Task):
+	description = 'Shrinking the volume'
+	phase = phases.volume_unmounting
+	predecessors = [volume.Detach]
+
+	@classmethod
+	def run(cls, info):
+		from common.tools import log_check_call
+		log_check_call(['/usr/bin/vmware-vdiskmanager', '-k', info.volume.image_path])