Tibetan sources mention Thub-sku-’od-zer-ma (“The Sage’s Image [Drawn with] Light Rays”) as the first ever image of the Buddha to occur in the Buddhist tradition. See, for example, the Ri mo’i rnam gzhag (p. 500). Historically, the image of the Buddha is said to have emerged much later. But the idea, and I emphasise “the idea,” that the Buddha’s image existed or originated already during the Buddha’s time is not invented by the Tibetans. The idea that the Buddha caused his image to be drawn on a canvas (or cloth) with his light rays can be found in the famous story of how the Singhalese princess Mu-tig-can became ordained via correspondance, narrated in the Vinayavastu (’Dul ba gzhi). My secondary Tibetan source for the moment is mTsho-kha-ba’s bKa’ ’gyur dran gso (pp. 515–516). According to it, the story must be found in (i.e. presumably in the sDe-dge edition of) the ’Dul ba (vol. ga (77th bam po). Check with ACIP!