Hello.
I'm not a GM nor a Mod but I can answer on this so..
Well, what you have to do is quite simple.
1. Open the KSC file that you wish to upload.
2. On left hand corner, top. You'll see that you have two options. ->"File(F)" and "Help(H)".
3. Click on "File (F)", click "Save As(A)"
4. Save it somewhere in your computer, make sure you remember where you saved it and feel free to add a new name to the file.
5. Once you done with it, just simply upload the file you just saved to some image hosting website.
I personally recommend on one of these :
http://imageshack.us
http://tinypic.us
http://hizliresim.com
Good luck.