If you want to code such things, then plugging terms like "wavelet transformation source code" into Google is a good place to start locating examples of prior works.
If you'd rather try applying such transforms images to see how such transforms actually work on an image, it's much easier to search for (e.g. "wavelet transformation photoshop") and locate plug-ins for applications such as PhotoShop than it is to code them from the ground up.
Back in the 1990's when I was fiddling around with images and wavelet transforms, (ANSI/NIST-CSL-1-1993 - Data Format for the Interchange of Fingerprint, Facial & SMT Information) coding was almost a requirement, because things like PhotoShop either didn't exist, or were in their infancy. If I were to do it now, I'd jump straight to a application like PhotoShop, download a plug-in, and avoid all the drama, angst, and heartburn of trying to 'roll my own.'