Who is responsible for original shipping if a clothing item doesn't fit?

[grindercb]

I sold a very nice shirt a couple of weeks ago.  The buyer is returning it because it didn't fit.

When I list clothing, I include not only the price but also a close-up photo of the tag showing the size and other information.  I also give measurements of the garment when laid flat and state as much.  For a shirt this would be the chest from armpit to armpit, length from the neck to the hem, and sleeve length from the neck to the cuff.  Also, I display those measurements on one of the photos, having drawn them in using MS Paint on my laptop.

So after I've taken care to make sure all sizing information is disclosed, the shirt still didn't fit and the buyer is returning it "according to eBay's return policy."  I don't mind getting a return but in a case like this, who is responsible for the original shipping, the buyer or the seller?

UPDATE: I am familiar with "item not as described."  In this case I described it in as much detail as I could and even displayed the measurements I took by drawing them on the photo using MS Paint on my laptop.  Also, the buyer has initiated a return where he stated that the item didn't fit.  From the responses I've seen it looks like he pays all shipping costs.  I just want to be prepared in case he goes to eBay to get more money back.

[stainlessenginecovers]

Buyer does; and has NOTHING to do with 

What it is

What reason they used

It's simply because you allow "30 day returns, buyer pays shipping' UNLESS!!: 

Buyer opens a return for the reason of 'not as described'; then you have to pay for it (and in full, including shipping they paid):

1 .) if you want it back

2.) you MUST refund either when you get it back or you can choose to simply NOT have to pay the return shipping, let buyer keep item AND you then, refund (in full ,including shipping THEY paid)

[wastingtime101]

It looks like you charged a separate ship cost on your clothing listings. If the buyer files a return with the reason "doesn't fit" then you are not obligated to refund their original ship cost.

If the buyer files a return with the reason "doesn't match description" and just puts "doesn't fit" in the comments, that's different. You'd be responsible for refunding in full, but the buyer should be reported for abusing the returns system by claiming an item wasn't as described just because it didn't fit.