Unable to add exact Image to guided journey task, color is getting updated

Summary:

Trying to add a background image for guided journey task added for personal payments page, but in preview/save it the color is not displayed same as image

Content (please ensure you mask any confidential information):

Tried to upload this image and once I click on preview / save it. The color is getting changed.

Do we have any alternate way

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):