[bug]: Image export bases children into image #211

Steps to Reproduce

1. Select a design with a frame or smething where there is an image background with children.
2. Export the design
3. Using the exported HTML, examine the epxorted Base64 image.

Expected Behavior

The background image should not include the children.

An earlier version of the plugin handled this correctly. If an image-like node had children, it would hide the children before exporting the image then un-hide them.

Actual Behavior

The background image has the children baked in.

Design Reference

@bernaferrari , you can use my test file to see this.

Screenshots or Videos

example: