I personally think it looks like a house cat. But the only way to determine size would be to have something in the picture for perspective. It could be 6" tall or 6' tall, with nothing to compare to there is no way to know.
However, even if it is a house cat, that doesn't mean there aren't large cats there too.
However, even if it is a house cat, that doesn't mean there aren't large cats there too.