I think there is a lot of confusion about bicycle stickers, decals and graphics.

If the graphics peel off a backing paper and have a self-adhesive carrier film like paper or vinyl, it's a label (or sticker).

Decals are a thin layer of paint (ink) with adhesive on the back that is activated by water, pressure (rub-on) or a solvent.

Stickers/labels can be printed by a variety of means including your color printer on vinyl or water-slide papers. The water-slide paper is not the same as a screen printed water-slide decal as the water-slide paper for home use has a carrier film on top of the adhesive already. It's a "sheet" of clear or white decal that you can print on and the decals must be carefully cut to size and trimmed. If you float a sheet of it in water you'll get one huge decal. If you float a sheet of true ink transfer water slide decals in water you will get individual decals.

True decals are nothing but a layer of paint (ink) and adhesive. They must be screen printed with special inks on special water-slide papers. The ink most commonly used was lacquer based and is difficult to find anymore so not too many people still print true water-slide decals. Water based inks react with the water-slide paper during the printing process and solvent based inks can be too thick. Pressure sensitive (rub-on) decals have special adhesive that is silk screened onto the decal art and use silicone papers so that when rubbed the printed inks will release. Ink transfer decals are super-thin, can easily duplicate fine lines and hollow letters and look like they are painted onto the frame when applied, they do not have a hard edge like cut vinyl stickers. Screen printing requires the use of spot color inks, the actual color must be mixed and matched and a different screen must be used for each color. This provides the most true and rich colors. Colors printed from a printer will always be a blend of color dots and won't be as rich. Because of the complexity of the screen printing process, it does not lend itself to low-production at a low cost.

Once you have the artwork, anyone with a color printer, a sheet of water slide paper (or vinyl) and a pair of scissors can make stickers or decals. It just depends on what kind of quality you can live with.

ALPS made a printer that can print some spot colors used a plastic ink melted from a tape cassette and can print white, foils and metallics onto vinyl and water-slide paper, but these decals must be carefully trimmed to size. Some vinyl cutters can be programmed to read registration marks from the ALPS printer (any printer) and can offer fine cutting capability. This is a good compromise for durability and quality, but the decals still aren't as good as real screen printed ink transfer decals.

Shameless plug: when we reproduced our Lotus decals we went with true ink transfer decals with pressure sensitive (rub-on) adhesive. They look exactly like the water-slide originals, but are easier to install and are more durable. Because we printed 100 sets (25 sheets, 11"x17") the decals are affordable.