Change some wording for image policy
Change some wording for image policy

change the wording to make it more accurate ,
image-size is the name of the policy of showing image size

Change-Id: Id3e0809465f24e174f8d32d3397efde3eb0dde73
Partial-Bug: #1515222

Tesora/tesora-api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,openstack/api-site,openstack/api-site,openstack/api-site,Tesora/tesora-api-site,Tesora/tesora-api-site,openstack/api-site,Tesora/tesora-api-site