Recognising the different technologies involved is something that I hope to find out in this forum.
These are transfers for sure as they have a carrier, the whitish coat on the back. However earlier transfers look the same from both sides of the glass. So what we have here is a later variation in the technology that is presumably cheaper. I would expect that only the translucent white is a vitreous compound (glass) and the other colours can fuse to other components on this layer. They could also be cold transfers. As you can imagine, I may be talking out of my posterior. I have mostly looked at earlier techniques so far and modern times have seen huge advances in printing technology. For instance the inkjet technology is so far only used to put one colour codings onto glass containers and processes these at an astonishing rate. It will not be long before entire vessels can be done in full photographic quality. If the technology gets cheap enough it could also see art applications.