Personal work for a story I was working on with my partner 4 years ago. It's set in the Regency so the clothing of the characters has to be very deliberate.
This snapshot is set during 1813, so the fashion of the time can tell you that the man on the left is out of fashion in his silhouette by about 20 years. Additionally, the waistline of his trousers is not quite high enough, and the pointed edge vest was more unpopular during this time. The button layout and the presence of epaulettes on this coat tells us that this is actually a military style jacket, and not just a formal one. In the story, the man on the left has only recently come into money, though he cares not for fashion, but still needs to look his best for formal events. All of this combined implies that he may have had this jacket before coming into wealth, and had decoration added to it to suit his tastes, giving the out-of-fashion silhouette meaning.
The man on the right may be more underdressed than his companion at first glance, but looking closer reveals that he is at the height of fashionable for his time. His trousers are sleek and high waisted, with a straight edged vest of finely woven damask (silk, although it's harder to determine exact material specifics in this style). And while he's not wearing a cravat, breaking from a fully proper outfit, the appearance of flounce in his shirt is more due to the undone-ness of it, rather than breaking from appropriate fashions. Still, he would be classified as a dandy within society, and so the flounce in his shirt is expected. Like rich people in our own time, the man on the right can dress in "casual" clothes around his house and they're still very fashionable and expensive. Son of an aristocrat, he is free to be an artist all day if he chooses, and walks among the grounds with sleeves rolled up and charcoals in hand.
Overall the goal was to capture a moment that couldn't be for that time, which was very fun to paint.
second image was in the costume design process.