updates image to correct legend (#375)

### Description

As per slack conversation with @allenheltondev, the image had the legend
flipped and a slight gradient. The new fixes resolves this.

### Issues Resolved

n/a

### Check List
- [x] Commits are signed per the DCO using `--signoff`

By submitting this pull request, I confirm that my contribution is made
under the terms of the BSD-3-Clause License.

Signed-off-by: Kyle J. Davis <[email protected]>

Author: stockholmux