Forum Moderators: buckworks
If your customers are using your designs to sell your product, that means they can order more from you, which can't be a bad thing.
Perhaps you could investigate a license for them to use the designs and graphics, so they can still sell your products, but you still ensure you keep ownership and control over the images.
If someone else wanted to put pictures and information about my products on their website and do all this promotion for free, then I'd think twice before cutting them off.
I wish I could advise more. If the designs are actual blue-prints - i.e. patterns etc. then I have misunderstood the problem (and in fact, I don't know why any of your customers should possess such documents!). However, if you are referring to promotional photography or sketches, I will again suggest a licensing agreement. Could you protect yourself by stipulating, as a condition of using any of a provided range of images, that:
- They will either place your logo on the image or acknowledge your brand name on the page as manufacturer / designer
- They will not sell any similar products on the same site or commission replicas from other manufacturers
- They will remove all images should you require them to do so, giving 5 days notice.
If you are having your designs stolen by other manufacturers, then I don't think your problem is with the customers showing photos of your designs - but with the manufacturers who stealing your creative work. Not being a lawyer or knowing where you are based, I cannot comment, but I suspect that you may be able to register or assert some form of copyright or similar to protect your designs.
<edit>with reference to jsinger's post - it is true that in the US you cannot copyright clothing designs - but you can copyright distinctive elements of a design, for example, a certain shape and arrangement of straps on many of your dress, or a distinctive motif.
There are other steps you can take before going the legal route. If you have already contacted the thief then the next step is contacting the host. If that doesn't work then report them to Google Spam report, or Google Adwords, Google Adsense, Overture Ads, or any other advertiser on their site. That may take a while to see results. If you're in a hurry the go the DMCA route with Google or any other search engine they are ranking highly with. You may need to send this to the host also.
This is assuming you have proof that the photos are yours. If they have been online for over a year the proof will be in the WayBack Machine and you can use that as 3rd party proof you had them online first (doesn't prove who owns them but this often works).