WhatsApp today released an update for its app for Windows Phone devices. This updated app v2.6.114 includes few UX tweaks and performance improvements which were under testing in the beta app over the past few weeks. In this update, image gallery has become significantly faster. When you go to Gallery for image selection, instead of All Images section, it will now go to Folders page.
You can download the latest update on your Windows Phone from the Store link below.