The color of your file may look different after upload because the EPS file format does not support ICC color profiles. This means that the EPS file format can not tell a computer or device the exact range of colors that should be displayed. So that means the device will “guess” what the colors should look like. If your file was created in Adobe Illustrator, the EPS file will be embedded in the whole .ai file, and the colors will remain consistent when opened in Adobe Illustrator. But any other programs other than Adobe Illustrator (including the one that Vecteezy uses to generate previews) can not read embedded AI info. Therefore, if you open up your EPS file in Adobe Illustrator, it will display the same colors as your initial design, but any other program will take a best guess at how to display the colors.