Application image cache files

I am trying to find where particular apps store their image cache files. For instance, if I customize an icon on a home launcher, where is the new custom icon image stored? Or if I create a new image in an app but the app can only restore it itself, there must be a place where it exists in the files. Could the images be stored within the database in a format that I can't extract via android functions? If so, how can I view or extract images stored in the database?