For about 3% of people with epilepsy, exposure to flashing lights at certain intensities or to certain visual patterns can trigger seizures. This condition is known as photosensitive epilepsy.
Photosensitive epilepsy is more common in children and adolescents, especially those with generalized epilepsy and a type known as juvenile myoclonic epilepsy. It becomes less frequent with age with relatively few cases in the mid-twenties. Many people are unaware that they are sensitive to flickering lights or to certain kinds of patterns until they have a seizure. They may never go on to develop epilepsy with spontaneous seizures. They could just have seizures triggered by certain photic conditions. Many individuals who are disturbed by light exposure do not develop seizures at all, but have other symptoms such as headache, nausea, dizziness, and more. They do not have epilepsy.
The banner, I believe will not cause anyone seizure. As they are not intense.
In addition, if anyone has such condition I believe that those 3% individuals know better to avoid looking flashing banners.