Howdy seaspray,
well I have an HP photo quality printer and it does just fine with standard photo ink. I also have the "testors" decal maker program, but more often than not, I make my own decals through mY photo editing software.....I have 5 different photo programs, all of which work fine. The adobe programs are my favorite, short of that, the photo explosion program and last but not least, the arcsoft photo editing program.
I find the designs I want online, usually in google images, save them as a .jpg file, then manipulate them in one of the programs, adjusting the size, color (if needed) and shape (if needed).
Be sure to use and "overspray" on the printed decals BEFORE immersing them in water. There are products made for this, but I use testors gloss cote or testors dull cote......which ever i have handy at the time. I let it dry, cut out the decal and immerse it, slide it onto the model and pat dry. Then add an over coat to the decal on the model.
Hope this helps,
Greg