The DMCA is really an overly broad, overly empowering piece of legislature which if effectively copyright infringement rules on steroids.
Basically, the end of the day summary is that if any form of content you use, whether it be text, graphic, audio, video, etc is not expressly permitted for use on your site (this extends past web sites by the way, but web sites are the best example), then you are potentially liable for the DMCA to be invoked.
It goes even further. Let's say I carry snow globes, and I take pictures of said snow globes from the manufacturers catalog and put them up on my web site to sell my product. Manuacturer decides they don't like this, so they go to their lawyers.
Next thing you know, their lawyer is sending letters of DMCA violation to not just us (

), but to our provider, stating that content in question must be removed within "x" period of time or they will sue the customer,

, and provider. Even better is that not only are we (

) compelled to comply, but our provider can within rights shut us down at will, with no reprecussions as they are simply obeying the nature and provisions of the DMCA. What is scary about this is that regardless of the claim, we are blameless, as is our provider until the legal matter is settled and even then we have an arbitrary amount of time to bring you back up, if ever.
This sounds really bad, and it is...I have dealt with one customer of ours who already had this happen although it was handled smoothly and to an amicable resolution (although their site was down for a week while they had to check and confirm the offending content was removed). I am not a lawyer, but I have looked into this a lot and there are many stories of how insane the DMCA is and how it's overly strict and broad provisions are being abused. The problem is that it will take a considerable effort to get anything changed on this law now that it is on the books (i.e. - time, money, and influence).
My personal advice for our merchants is to get a digital camera, take pictures of your merchandise, and use them. Not only should this completely CYA, but it will add a unique look to your product as compared to the same pictures everyone else has. And yes, let's say your wholesaler had the DMCA applied to them....believe it or not, you too are affected.
It's late and I am not in my best writing mode or frame of mind so I will leave any further discussion and commentary for tommorrow or the next day

Captain's Super Special Ultra Summary -
"DMCA Bad. People get sued. Use only your own original content and you should be good"