Please follow the steps below to add a "Background image" to various sections like header, footer and body using the Prime Stylizer.
1. Launch the Prime Stylizer by clicking on Settings Gear (SharePoint 2013/2016) or Site Actions (SharePoint 2010) and selecting the Prime Stylizer option.
2. Open the Header section and in Background image select Add Image.
3. It will popup a window that will allow you to select an image file. After selecting an image click on the Apply button to apply background image.
4. Image will be applied in the header as below:
5. Below the Background-image option there is Background-repeat option to apply different repeat styles for the image:
- Repeat (The background image will be repeated both vertically and horizontally).
- Repeat-x (The background image will be repeated only horizontally).
- Repeat-y (The background image will be repeated only vertically).
- No-Repeat (The background-image will not be repeated, this should be default option if none is selected.
6. There is also a Background Position option available to set the image alignment.
- Left (aligns the background image to the left).
- Right (aligns the background image to the right) .
- Center (aligns the background image to the center position - this should be default value).
Similarly, you can add background images to General and Footer Sections also.
Note : Background images are uploaded in to Emgage Prime Stylizer Themes library inside Images folder for all themes of particular site collection. Therefore, if you upload an image with a duplicate name then it will overwrite the existing image even if it is for a different theme or section.