If I have a gif on a site that loops continuously. Is that okay or does it violated the 'can't have repeating flashing stuff' rule?
Most of the time animated gifs will be accessible. There should be a few things to keep in mind though to ensure this remains true. For example, ask yourself if there is another way that the message can be communicated. Would a still image do? If not, think about providing an alternative or some way that users can forgo the animation. A useful tool when checking your gifs for accessibility may be this Photosensitive Epilepsy Analysis Tool. The thought behind this is that you can make sure the animation won't trigger seizures in people who are sensitive to them.