You will need the image's direct link, commonly ending with the file's extension (.png, .jpg, etcetera).
Try manually typing out the [img] tags, it's commonly easier.
[23:23:53] <AndChat|700625> Blue eyes ultimate dragon best card
[23:24:29] <AndChat|700625> You know the one with 3 heads
[23:24:39] <~Lightningkid> just like my dick
[11:35:40] <box> Hampa suck
[11:36:21] <hampa> not the first to tell me that today