The quests named The Second Painting and The Third Painting do not have their location marked in the map as opposed to their description:
To help a bit with this situation, you can find a hint for the areas in the list below:
The Second Painting
Rookborne Basin
Windscour Savannah
Perinoor Ruins
Hasla
Sanddeep
Hellswamp
Cinderstone Moor
Karkasse Ridgelands
The Third Painting (two different locations)
- Marianapole and Austera
- Mahadevi and Lilyut Hills
- Gweonid Forest and Villanelle
- Silent Forest and Solzreed Peninsula
- Tigerspine and Dewstone Plains
- Airain Rock and Falcorth Plains
- Arcum Iris and Two Crowns
- Aubre Cradle and Sunbite Wilds