A Continuation of the Triumphant and Couragious Proceedings of the Protestant Army in Ireland.
It may be an April fool, but this is a tricky image to date. It appears in several publications and at first sight looks a little dated for the 1640s, with the baggy breeches and stiff collars, though it may be a representation of the trained bands of London who often drilled in their best, possibly slightly old fashioned clothes. However, as has been pointed out on several occasions since I posted the image, their breeches do look like German pluderhosen of the period, not standard English breeches.
The 1640s Picturebook 