I love to use images available through Creative Commons to create some of my own designs. You do need to check the license and make sure that they are able to be modified and used without attribution for use on a POD product.
One site that is great for this is Pixabay and I do use them quite a lot. I have a couple of Zazzle stores that are entirely created using this sort of designs. An example is this Christmas card –
I took an image of a bull terrier and added an image of a Santa hat to the dog, popped them both on a bright background and added text. I loved the result, it was also fun trying the different Santa hat images that were available to get just the right one.
Another example of this can be found on an older post of mine where I tell you how I created my Catherine Parr Greeting Card.
The fun thing about Zazzle is that you can have a number of different stores and do different things in them ie have one based on your own photography, one based on your own artwork, one based on remixed creative commons work, one based on geometric or text based designs, the ideas are endless.
Here’s a look at a couple of my stores and how they differ –
Zazzle does well with all kinds of designs, but to be honest a lot of the remixed creative commons designs do outsell a lot of my own art/photography (except for 3 of my bestsellers that is).
I think the key to success if finding your own angle and making sure that you do make changes to the design, otherwise you’re competing with thousands of other identical designs because you didn’t create this idea!