2. "One–to–One" Rule
A DC metadata description should describe exactly one
resource
a) how to represent media-type of items in collection?
my:collection dc:format "img/jpeg"
[dcterms:IMT]  ?
No, the media-type applies to the item(s)
b) how to represent dates of creation of items in collection
my:collection dcterms:created "2004-01-01"
[dcterms:W3CDTF] ?
No, the creation of the collection is not the creation of the items;
we've used dcterms:created for the dates of accumulation