Picture books are so unpopular these days at the Children’s Book Shop in Brookline, Mass., that employees there are used to placing new copies on the shelves, watching them languish and then returning them to the publisher.

“So many of them just die a sad little death, and we never see them again,” said Terri Schmitz, the owner.

The shop has plenty of company. The picture book, a mainstay of children’s literature with its lavish illustrations, cheerful colors and large print wrapped in a glossy jacket, has been fading. It is not going away  perennials like the Sendaks and Seusses still sell well  but publishers have scaled back the number of titles they have released in the last several years, and booksellers across the country say sales have been suffering.

The economic downturn is certainly a major factor, but many in the industry see an additional reason for the slump. Parents have begun pressing their kindergartners and first graders to leave the picture book behind and move on to more text-heavy chapter books. Publishers cite pressures from parents who are mindful of increasingly rigorous standardized testing in schools.