where does ('<<Graphic-Signature>>') and ('[sig]') come from?
That is standard text inside the template. It is not the name of an object.
I am having a hard time understanding how to locate the object.
If you insert images without reference to a file you cannot loacte a filename. Only if you inserte links it makes sense to read out "StreamName". However you can assign a name when you insert an object.
You get a reference to a TWPObject by InsertGraphic.
You could set the property ObjName but that is not really useful, since the same objects can be used more than once in a file.
You can use this code to insert your pin
obj :=WPRichText1.TextObjects.InsertCopy(Image2.Picture.Graphic,300,300);
obj.Name := 'XYZ'
And this code to locate it later
WPRichText1.CodeMoveTo('XYZ',wpobjImage, [], [wpCompareName]);