I’m really sorry to hear of your bad experience. Let me give you some additional info on what is going on.
The NAS is working in the background transcoding pictures - converting them into thumbnails, and formats for your mobile device. That way when actually viewing photos - the amount of data actually being sent over is small and therefore downloads fast and doesn’t eat a lot into your data plan.
This approach was also selected because people usually have DSL / cable modem with slow upload speeds.
How large are your photos? For a 4-5MB photo, it should take about 30 - 45 s to convert. So for 4600 photos, it should take about 38 hours. (It’s a one time conversion). The CPU on the NAS is designed for low power consumption since it’s left on all the time - hence why it takes so long.
Another thing to check is if the database on the phone is actually updated since for 36 hours I’d expect to see more of your photos converted (unless you have pictures that are more like 10MB in size). People clear cache in settings and then try. Auto-reload works but the algorithm chosen was to not ping your device often (to conserve battery power). This will be improved.
In case you’re wondering, yes I’m an employee of WD (Director of Engineering for the mobile group) and read the groups as I care about what people like you are thinking and feeling about the products. We are continuing to improve the product (we just did an update of WD Photos to 1.1.1) and there are teams working the backend (transcoder/mionet) to improve that experience as well.