I took these photographs in southwestern Poland in mid-June 2015, in a patch of second-growth wood next to a scrubby overgrown field. I only saw this bird briefly, and it didn't vocalize, so at the time I hesitated in making an ID, as I've got very little experience with European warblers. Looking over my pictures now, it looks to me like a Willow Warbler. Am I right in saying that, while Willow Warblers can have dark legs, Chifffchaffs can never have light legs, so a bird that looks like one or the other and has light legs is a Willow Warbler?