The filenames for geocoin custom icons are simply numbers. It stands to reason the early numbers are the earliest trackable geocoins with
This page creates image links for numbers 1 - 350 to see which ones exist. Links are attempted to both GIF and PNG files for each number
in case the icon is in one format and not the other (or the two are different).
A missing image indicator means a geocoin icon doesn't exist for that number.