For as long as WhatsApp has been on iPhone, any images included in messages have been replaced by a camera emoji in notifications, so you had to open the app to see the attached media.
Similarly, GIF messages sent over the chat platform are traditionally represented in notifications by the space invader emoji, requiring users to open WhatsApp to view the content.
That behavior is set to change in version 2.18.90, released today, with support included for full media previews. On devices with 3D Touch, a hard press on notifications should reveal the media without having to open the app. Alternatively, users can swipe left on the notifications and tap View in the revealed menu.
It's also worth noting that the media preview feature allows users to download images and GIFs directly from the notification if they have disabled WhatsApp's media auto-download option.
According to WABetaInfo, the media preview feature isn't working for everyone who has updated just yet, but WhatsApp is apparently aware of the issue and is aiming to fix it server-side within the next few days.
Also in version 2.18.90, WhatsApp is introducing a feature that flags suspicious links sent over the chat platform. When a message is received that contains a link, WhatsApp analyzes the URL characters locally in order to detect if the link is suspicious and alerts the user in the chat thread.
WhatsApp is a free download for iPhone available from the App Store. [Direct Link]