I am trying to set an image to my signature that points to an external url image file that is located here.
It is an image created by libgd and is constantly updated, and will always be 500 x 90 px and ~15 Kb. I can lessen these params even further, but it is no use, and I always recieve this 'invalid file' problem from my signature.
Does anyone know why this could be happening?
Invision Forums allow the image, but this vBulletin is a little stubborn.