In the html template I have this style with a dynamic image:
<div id="component-id" [style.background-image]="'url(www.domain.com/path/'+bgImageVariable+')'">
<!-- ... -->
</div>
or
<div id="component-id" [style.background-image]="'url('+bgImageVariable+')'">
<!-- ... -->
</div>
you can use in second way by adding URL path in a single variable. for example
bgImageVariable="www.domain.com/path/img.jpg";
use this and set height and width of div tag as per you need
<div id="component-id" [style.backgroundImage]="'url('+bgImageVariable+')'"></div>
Use instead
<div [ngStyle]="{background: 'url(/img/' + item.img + ')', width: '200px', height: '150px'"></div>
or
<div [style.background]="'url(/img/' + item.img + ')'"
[style.width.px]="200" [style.height.px]="150p"></div>
See also In RC.1 some styles can't be added using binding syntax
You should do that as the +Günter Zöchbauer second part answer generates unwanted supplementary style background-position: initial and background-size: initial on Safari at least.
Note that I only set the background-image style:
<div [style.background-image]="'url(/img/' + item.img + ')'"
[style.width.px]="200" [style.height.px]="150p"></div>