Goal: Load an image with a dynamic source. If no image is found, then load a placeholder image instead.

This should demonstrate what I'm trying to do, but I don't know how to conditionally set validImage based on whether the first img src is valid.

<img *ngif=validImage class=thumbnail-image src=./app/assets/images/{{image.ID}}.jpg alt=...>

<img *ngif=!validImage class=thumbnail-image src=./app/assets/images/placeholder.jpg alt=...>

validImage should be true if src=./app/assets/images/{{image.ID}}.jpg returns an image. Otherwise it would return false and only the second img tag should show.

There are obvious work arounds like storing a list of all valid image sources, but I'm thinking there is a better way to accomplish this.

Any suggestions on the best way to implement this in Angular2 would be greatly appreciated.