Interesting jpeg behavior in AD

[Kuttyjoe]

I wasn't aware until this morning that vector paths could be saved with jpegs but that started me down a path of investigation, and led me to what I think is a problem in Affinity Designer.  To get right to the point, I opened a jpeg this morning that I downloaded from the internet.  It was a t-shirt image.  The image opened up in Affinity Designer, but was not a t-shirt.  It was a transparent shape of a hoodie, with the red t-shirt visible but cut in the shape of the body of the hoodie. The layers panel shows two masks. One is labeled "Hoodie silo".  That told me exactly what I was looking at. Whoever created this image was using a blank document, bringing in various garments then using vector paths to cut them away from their backgrounds to create images that can be overlayed on different backgrounds while having the same dimensions for the bounding box. This is a typical workflow, but I would expect to see all of this in a native Photoshop file, not a jpeg.  I proceeded to open this same file in Photoshop and all was made clear.  The masks that were active and engaged when opened in AD, were actually just vector paths in Photoshop, not active or engaged.  You wouldn't even know they were there if the paths panel is not open/visible. Someone used a blank document, imported various garments, used vector paths to cut the garment from the backgrounds.  They did a hoodie first, then the t-shirt.  When the t-shirt was saved, the vector paths for the hoodie were still in the document and were saved with the document, even in jpeg format.  When the document is opened by Affinity Designer, AD decides that those left over paths are actually active masks when actually, they're just left over junk that shouldn't be there, but certainly should not be considered active masks.  Affinity Designer sees the random vector paths and automatically converts them to active masks and presents it as shown in the attachment.