Hi Fixx, As MattP explained an Image layer keeps all the original image data intact and Affinity use it when you export your document (contrary to a Pixel layer which becomes detached from the original data). Embedded document layers are a different thing. They can contain an entire document - not just images - , but shapes, text, layers etc depending on the type of document you are embedding. If you double click an embedded document object/layer on canvas, Affinity will open it in a new document tab with all different objects it contains available for editing. If you change/edit them, the embedded document object/layer you double-clicked in the original document will be updated accordingly.   You can embed several types of files/documents, from PDF, PSD, SVG's etc. all usually containing several objects types (text, shapes other layers etc).