so as long as tumblr keeps this, here's the tumblr version of etiquette that was maintained when twitter's quote-retweets affected artist visibility/notes:
for art that someone has added reblog commentary to (or removed the caption from), reblog from the source
otherwise, avoid adding reblog comments to art (as this will affect the artist's notes/visibility)—utilize tags and replies to provide commentary (which artists will absolutely appreciate)
reblog comments are comments added to the body of a post, not the tags and not replies.
