This is a pretty specific, probably rare, situation that I accidentally found while previewing a page early in the process of building it.  The gist is that when a page contains an image and the only model is a ui-only model, the page content will not load.  However, either adding a model with Salesforce as the data source OR removing datasource=“salesforce” from the image tag XML fixes it.

Given that this issue is limited to pages using only a UI model, I am guessing it won’t come up much, but figured I’d share in case anyone else gets stuck on this.  Or in case there is a need to have a page with an image that only contains UI models.

Some details:
I found this when I started building a page with an image in the header and without any models; checked the preview and it loaded fine.  When I added a UI-only model, the preview page loaded, but did not display any content and there were no error messages in version 9.5.6.

Thinking maybe it was fixed in a later version, I tested this in a sandbox upgraded to version 10.0.5 and it still would not load the content, but in the later version, I got the following error message: “There was a problem rendering a component of type image: Cannot read property ‘getImageSource’ of undefined.”  This occurred when the image source was either a static resource or URL.  When I change the Data Source Type in the page builder from “salesforce” to “Ui-Only” the error message went away, but the image did not show up from a URL.

Found the solution after some testing – either adding a Salesforce-sourced model or removing datasource=“salesforce” from the image tag XML.