image size does not appear to have any affect when a progress bar's image is set to tile

When trying to set the image size for the image that is tiled in a progress bar, this does not appear to have any affect. The expected result would be for it to modify the size of the image so as to increase or decrease the number of tiled images applied to the progress bar.

1. Open editor
2. Create a new widget blueprint
3. Open the new widget blueprint
4. Add a progress bar to the designer tab
5. Change the brush in the style of the progress bar to something that is not square
6. Set the brush to "Image" and tiling "Horizontal"
7. Change the image size
8. Notice that the image does not change size or proportion