Image link doesn't take up capacity. I think the explanation is that it's so common that everything has the hardware in order to be compatible, while others like low-light vision and ultrasound might need additional components.
Either way, glasses (maximum rating 4) with image link would still have a full 4 capacity. Flare compensation is 1, a trideo camera is another 1. That means you can slap on Ultrasound (2 capacity), or Thermographic, Vision Magnification, or Vision Enhancement which take 1 capacity. Or if you feel like it you can build in a different sort of sensor if you really feel like it, but most people use Sensor RFID chips for Motion Detectors or Radio Sensors or such. Radar sensors combined with an orientation system or chip of some sort (GM discretion) mapsoft can help your team navigate even if you're in poorly-charted areas because the orientation system description mentions map-editing software.
If you're running a tacnet, there are additional uses out-of-combat that you can make use of if you've got a skilled Face - a camera with Thermographic and sensor software Lie Detection gets a bonus for detecting falsehoods.