Garden Weed?

These tiny violas keep popping up in my garden like weeds, only if you take the definition of a weed as "a plant in the wrong place", then I can't treat them as such as any flower in my garden is to be celebrated. 

Actually, I believe them to be a wild flower in the viola family, most likely the Early Dog-violet - an unflattering old name given to unscented violets, as opposed to the scented sweet violets, as being "only fit for dogs"!