yeah, but...
"decals" are clear-- they are very thin pieces of plastic or celloid that have printed images. they are sold mounted on paper.
you soak the decal in warm water, and then carefull slide it off the paper, and onto a surface (usually, but not exclusively glass--some decals are designed for putting on plain tiles, to make them look like hand painted ones)
the decal has a somewhat water soluable glue-- and it sticks to the glass (or tile) permentantly (to remove you moisten, and scrap with a blade.. no amount of soaking will loosen the glue!)
they are commonly sold in home decorating stores and art stores and craft stores (for home use)
Colleges and Universities make decals for rear view windows that are usually just the name of the college or university.. the letters are outlined, and the decal, placed low on the window does not significantly interfer with the view out the window.
some organization, (like Police Benevolent Organizations) also offer decals.. these are about 10 cm to 20cm (4 to 8 inches) in size(some are round, some are shaped like a sheild, some are square or rectanglular) --and are often displayed on drivers side rear (passenger) windows
some universities also have parking permit decals and these are also displayed on passenger windows. (usually these are smaller, less than 10 cm square.)
decals are also used to decorate china--and create what looks like hand painted designs.
