Image not being picked up

Trying to implement a background image for a webpage using a UI module. But the image is not being picked up while the path is being recognized (404 files not found error) and the CSS code is connected properly (tested by making the background purple). So my question is where should the images be put in the file structure for it to be recognized? Unfortunately, the Mendix docs and communication on the proper folder structure for design and styling are very barebones. Weirdly the only image that does get picked up is the work-do-more jpeg provided by Mendix from the resource folder. Putting our images there does not have the same effect.   
1 answers

Did you see this documentation?  see below a section screenshot which mention how you can use the images in your CSS files