Was just wondering what you thought of someone redrawing one of your (or any artist for that matter) character dawings. I was having a discussion with a friend who also draws and was wondering wht your take on this is.

I've often said that swiping is a good way to learn. If another artist has already solved certain problems presented by a shot, a pose, a bit of action, why not "borrow" his/her experience?

The problem arise when it ceases to be a learning experience, and becomes standard operating procedure. Like, if whole websites can be devoted to tracking an "artists" use of swipes, he's clearly taken it too far.

If trademark information (or credit due) is included would that in turn make it more of a homage?

The issue of "swiping" (i.e. using other people's art as the basis for one's own) has various legal and ethical dimensions.

In the Avengers/WCA homage above, there is no legal issue as both images are work-for-hire product copyrighted to the same company and depicting the same character.

Ethically, using swipes can be seen as passing somebody else's work off as one's own. Using an iconic cover in a clearly evocative way while writing an acknowledgement does not claim ownership in the design. I've read (don't remember where) that some people have a personal policy of asking for the original artist to receive a design fee, but that is by no means considered a requirement.

A lot of artists, great artists, swipe and imitate, or use already existing (copyrighted) images as reference. But they also alter the images to fit the story/panel, to adapt it to their style, to accomodate overall page design. Usually to an extent that would be considered "transformative" in the eyes of the law.

The uses that are most frowned upon are:
1) when the swipes so closely resemble the original stylistically as to not be sufficiently "transformed", especially if the swipe has bad drawing in it, that makes the original artist look bad (Lichtenstein, I'm looking at you).
2) Swiping a lot from the same source, entire page.compositions or most of a book, so it comes close to plagiarising the story. 
3) Swiping where storytelling is sacrificed because the artist only draws positions and poses he can trace or copy, and does not make an effort to adjust poses or come up with new ones.

Homages are OK, but the term has been abused at times.

This is called a "recreation", but seems more of an homage if the pose is only thing being recreated.

[X-Men #137 ala Thundarr]

The way I've always looked at it is...with an homage, the artist is intending for the audience to KNOW it's a recreation of a previous work (kind of like a tribute).  JB's various and numerous homages to FF #1, for example.

With swipes (Liefeld and McFarlane) they are presented as originals with no intention of the audience knowing it was taken from a previous piece.

In other words...you trumpet an homage, you try to get away with a swipe.