Spaces: Custom images should respect transparency on source image.

[JFQueralt]

Problem

When customizing a Space, the source of the icon can come from an external image.
When these images have transparent background, this is not reflected in the final render. The icon is rendered with full white background (light site) or full black background (dark site).

Request

Please respect transparency on source images. It may feel like a small thing and yet it is visually displeasing that a properly crafted image does not merge smoothly with the interface.