A compulsive snapper of all things stylish, kitschy or arcane, Susanna Lau, the blogger known as Susie Bubble, wandered earlier this summer through the Meiji Park flea market in Tokyo taking pictures of vintage Hawaiian shirts, toy robots and tiny Minnie Mouse dolls to upload to her phone. 

A handful of years ago, she might have archived those images, marking them for her eyes only. Now she has made them accessible to anyone with a camera phone and an Instagram account. So it didn’t surprise her, Ms. Lau said the other day, that when she returned from her travels, “I saw some of my images on designers’ mood boards.”

Her experience is hardly unique. In recent months designers of every stripe and aesthetic persuasion have turned to Instagram for a glimpse into the lives and tastes of their fans — bloggers like Ms. Lau, stylists, models, artists and random visitors, who in turn are snapping and posting their way into designers’ consciousness, onto their mood boards, into ad campaigns and, directly or obliquely, onto their runways.