by default it stores screenshots in an obscure folder under your user id, by game id. (something I've made symlinks to get around for ages). you can also turn on uncompressed screenshots and provide a directory, at which point it just dumps every screenshot there without any structure (still get timestamped files, at least).
both of these options suck and I really don't see why "store my screenshots by game somewhere I specify, optionally uncompressed" is too hard to implement in two decades.

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