By “upload theme package,” what I believe my colleague, khoand, means is that you will need to create a new set of files for the particular color theme you want. You can view the files and images you will need to create by viewing the same for the other color themes – which are located at templates/ja_methys/core/themes
For the images, you can utilize the JA Methys source files or you can pick a current theme and modify each image individually – saving the newly created color theme images into it’s own theme directory.
After you have done this, you then need to create he relative CSS for your new color theme. A “quick-tip” way to do this is to simply duplicate the CSS files from one of the existing themes, rename it, and modify the image calls for the new images you just created.
Yes, it is going to take a bit or work, but that’s how you can create your own new color theme.