Use media files as background for selected feature item

[CoachBirgit]

As user, I want to use a custom chosen background file as repeat pattern on a selected item. I want to choose the item i.e. the hat or coat and apply a media file of choice to use as a background for this specific item instead or in addition to the solid color.

The file could be a repeatable tile as .jpg, .png or .svg. It should repeat on both axis.

it would be nice to have the same media uploader as used in den WordPress editor.