>>Using 'ng-src' rather than 'src' might be enough. If not then I'd suggest pre-computing the value returned by your getImageData() method, storing that as an additional property of the dailyCodes model and using that property name as the ng-src.
>
>I think pre-computing sounds a better idea, so I'll add it to my view model and adjust the code to get it as a property instead.

You should still use ng-src rather than src....... : https://docs.angularjs.org/api/ng/directive/ngSrc