Concon-collector is a Japanese mobile / web game revolving around the collection of "Concons", fox spirits.
The game uses art contributed by various artists. Often, there are specific foxes with several different versions using art by different people.
Normally, the official art used within the game is downsized to 200px or less, and higher-resolution artwork must be posted by the artist themselves.
Concons typically have special art that can only be viewed by a player who owns a given Concon. These can either be upsizes of the portraits normally used by Concons, or in other cases they may be different images entirely.