Hi Sidhant!
Try with this line inside main.scss: background-image: url(./splash.gif);
It worked on my app.
Hi Sidhant Dorge,
The URL path you have Given is wrong, you will have to target the Folder in which the .gif file is present ( You have given your path from Your local machine like E: ) . For example if you gif is in Theme/Web/loader.gif the path will be like
background: url("web/loader.gif");
Note : Theme folder Will be you root folder.
The import you have done for Custom.Scss will be similar to the Above( not the whole path including your local System path).
Hope it helps!!