praise, picture title
讚 centers on expressing strong approval or admiration: praising someone or something. The 'picture title' sense is a specialized application where a title serves as a form of commendation or descriptive praise.
讚 combines 言 (speech) with 贊, which likely contributes both sound and the idea of assisting or supporting, together suggesting praise expressed through words.
The left side 言 is speech, and the right side 贊 looks like a person presenting something valuable. Imagine someone speaking words of praise while offering a gift: 讚 is to praise.
For サン, picture the sun (サン) shining down as a crowd praises a hero: sun -> サン, and the warm light feels like approval.