Who owns what, and when?
Intellectual property is a serious issue.
On 99designs, designers agree to upload wholly original artwork and, subsequently, they own the rights to their submissions. This is true all the way up until one of their designs is selected as a winning design entry. Then, and only then, do they agree to transfer their rights to that particular entry over to the contest holder. They do this via the Design Handover, and once done, the contest holder becomes the new owner.
If a designer creates several iterations of a single design, but the contest holder only purchases one of those iterations—then the rights to those other designs remains the property of the designer. The contest holder can, of course, negotiate with the designer for the transfer of rights to multiple designs.
If the contest holder does not purchase a designer’s work, it remains the property of the designer.