"... for those photos which have attribution EU2015.LV reproduction is authorised, provided the source is acknowledged" (Secretariat of the Latvian Presidency of the Council of the European Union).
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the
same or compatible license as the original.