To post images, you need to host them on a website such as photobucket or the galley area here on RB. Once the pictures are loaded to a website, you can add them to your post by clicking on the "Insert Image" icon
within your post box. It will pop up a box where you paste the http:// address of the image.
The line for what can and cannot be posted here is pretty liberal. As long as you aren't breaking any copyright infringements, posting offensive material, bashing other members, or selling items/services (outside of the marketplace area) you are probably fine to post it. I'd love to see you create a step by step post in the DIY Projects area for how you make your LED lighting system. BTW- How long have you been using your LED lighting and what do you think it would cost to make a LED system that would work good over a 6'Lx24"Wx30"Tall tank?