RRDG load image with relative path

Once an image is loaded into RPE, the original image is no longer needed as RPE will save the loaded image into its internal Resources folder.
Could you please elaborate what you are trying to achieve?

If you are "Loading" the image, you need to browse to the image and load it, which will be included in the RPE document template archive (commonly called RPE template or .dta file).

If you are setting "Content" property for the Image element, it can be either full path to the image file or path relative to the template. The Content can also be set to data attribute (ex. dataSource/artifact/wrappedResourceImageURI)