PALO ALTO—Twitter Inc. on Thursday announced the launch of a tool through which users can showcase non-fungible tokens (NFTs) as their profile pictures, tapping into a digital collectibles craze that has exploded over the past year. The feature, available on iOS to users of the company’s Twitter Blue subscription service, connects their Twitter accounts to crypto wallets where the users store NFT holdings. Twitter displays the NFT profile pictures as hexagons, differentiating them from the standard circles available to other users. Tapping on the pictures prompts details about the art and its ownership to appear. Like other tech companies, Twitter is rushing to cash in on crypto trends like NFTs, a type of speculative asset authenticating digital items such as images, videos, and land in virtual worlds. The social media platform last year added functionality for users to send and receive Bitcoin. Sales of NFTs reached some $25 billion in …