When working with PlotShop you are able to import different image files, add text blocks, and draw objects. You then save the information, on the canvas, to an object file.
An object file is a storage file containing information about the objects placed on the canvas (location, fill, height, color, path of where to find the image file, etc.).
The purpose of the object file is, to save the location of each imported image file, overlay the added objects and any annotations for later recall. It allows for future editing of the canvas.
The object file is a format dependent file. It is strongly suggested that the object file not be edited outside of PlotShop as accidental corruption may occur.