Two options:
1. Go to vistaprint.com and make a bumper sticker with those flowers. Cut them out, and you've got flower stickers.
2. Go to officedepot and buy full sheet white shipping labels, print the flowers at home, cut them out, boom - flower stickers. This one has the downside of not being water proof, though. Inkjet printed stuff will bleed as soon as water touches it. There's a hack for that too, though. Before you cut out the flowers, cover them with clear packing tape. Then cut them out. Not an ideal solution, but still decent.