In this context, "clipart" and "SmartArt" are more likely to look like illustrations than a photo. Both of these options typically consist of stylized graphics or illustrations rather than realistic photographs. "Vector" can also be illustrative depending on the design, but it may not be as straightforward as clipart or SmartArt, which are specifically designed for illustrative purposes.
So, the best options that look more like illustrations would be:
- SmartArt
- clipart