Hi there WhosAdzer!
So, you have a couple of problems here but we're going to try to work them out. :) First, I need to know what your objective is. Did you create this thumbnail image? Or did you find it and thought it was perfect for showcasing your Let's Play? Second, you only have one image that I can see, therefore you'd need to post at least three other pieces for this to qualify as a gallery. Third, since this is related to your Light Platinum Series, it would normally be posted along with your LP, which belongs in the
Let's Plays, Guides and Reviews section.
So, here's what you can do. You can post your LP and I'll either close this or move it over to the right section, you can make three more pieces of art and keep this gallery, or lastly, I close this and you get back to me at a later time when your further along in your project. :)
I hope this was a little helpful for you. Just make sure, before you post anywhere else, you read each sections rules okay? That way, this kind of stuff can be avoided. Oh, and a small suggestion, keep in mind that there's a time and place to talk about your YouTube Channel.
Please get back to me about what you want to do and good luck!