It's a convenient alternative to the Filename property. Is recommended to be used with RImage arrays. For example, if you have a list of images, that need to be shown in different places in your application, is recommended to create an RImage array with all the pictures, and then attach a picture from the array to every RImage that needs that picture.
Return value:
Returns another RIimage from which the image data loaded, or null if none.
Example
// create an array ...
var[] image_list;
// create a RImage with no parent (a virtual RImage in order to keep the picture in it)
// load one image
image_list["my_image1"]=new RImage(null);
image_list["my_image1"].Filename="image1.png";
// load another image
image_list["my_image2"]=new RImage(null);
image_list["my_image2"].Filename="image2.png";
// ... and so on ...
// then, if we have two RImages that need to render the same picture ...
var some_image=new RImage(vertical_box);
some_image.RenderImage=image_list["my_image1"];
some_image.Show();
// render the "other_image" that shares the same picture with the "some_image" ("my_image1")
var other_image=new RImage(vertical_box);
other_image.RenderImage=image_list["my_image1"];
other_image.Show();
// and another one loading the remaining picture.
var other_image2=new RImage(vertical_box);
other_image2.RenderImage=image_list["my_image2"];
other_image2.Show();