What is the full macro? How is the macro being called? Are you just typing it (cutting and pasting) it into chat, or is it a collection macro, or an ability on a character sheet, or in the description of an attack roll, or something else? When I just put [img]( <a href="https://media1.giphy.com/media/l0MYHq0IFikDrVQOc/giphy.gif" rel="nofollow">https://media1.giphy.com/media/l0MYHq0IFikDrVQOc/giphy.gif</a> ) into chat it works, so it'll help if you also describe how it's not working - is nothing being shown in chat, or just the image is missing, or do you get a broken link?