LC2020

Hello, I have managed to embed an image into a post with ThingLink - I copied the embed code from ThingLink website and pasted it into the 'embed code' section on a post on Square Space. However Platform 7.1 templates don't allow people to embed images into galleries, and I have checked 7.0 which also do not allow for this. Would anyone know how I could embed an image from a third party website into a gallery block on squarespace please? Thanks!