The images used in this factbook are either
1. In the Public Domain, most due to expiration
2. Free to use under Pixabay's license (CC0)
3. Creative Commons, attribution required

The ones that require attribution are as follows:
Prehistory
Filitosa https://en.wikipedia.org/wiki/File:Filitosa_oppidum_1.jpg (CC BY-SA 2.0)

Ancient History
Tomb https://commons.wikimedia.org/wiki/File:Reproduction_of_Thracian_tomb_2.jpg (CC BY-SA 3.0)

Transition and Unification
Ampitheatre https://commons.wikimedia.org/wiki/File:Bulgaria_Bulgaria-0785_-_Roman_Theatre_of_Philippopolis_(7432772486).jpg (CC BY-SA 2.0)
Fortress https://commons.wikimedia.org/wiki/File:Klis_Fortress_-_a_view_from_south-west.jpg (CC BY 3.0)

Age of Discovery
Cathedral https://en.wikipedia.org/wiki/File:Se%E2%80%99_Cathedral,_Goa.jpg (CC BY-SA 3.0)

The Lily Revolution
Protest https://commons.wikimedia.org/wiki/File:Revolu%C3%A7%C3%A3o_dos_Cravos.jpg (CC BY 4.0)
Monument https://commons.wikimedia.org/wiki/File:Lisboa_Monumento_25_Abril.jpg (CC BY-SA 3.0)

Aovelalean War
(top) https://commons.wikimedia.org/wiki/File:Bundesarchiv_Bild_101I-163-0319-07A,_Griechenland,_Artilleriestellung_auf_freiem_Feld.jpg
(bottom) https://commons.wikimedia.org/wiki/File:Statue_of_Victory_(9454519944).jpg
Post-War
AOPP https://commons.wikimedia.org/wiki/File:%CE%91%CE%BD%CF%84%CE%AC%CF%81%CF%84%CE%B5%CF%82_%CF%84%CE%BF%CF%85_%CE%95%CE%91%CE%9C-%CE%95%CE%9B%CE%91%CE%A3.jpg
Contemporary Social
Feminist Protest ©Universo femminile
Pride https://commons.wikimedia.org/wiki/File:Gay_Pride_Toulouse_2014-3265.jpg (CC BY-SA 4.0)

The port image was found from https://www.ancientportsantiques.com/a-few-ports/leptis-magna/image17/