Could I get a complete explanation on the following two rules? I am new to both this game and online art creation but I am fairly handy with drawing and coloration. I would like to try creating a skin but I dont want to make a mistake.

•  In case of referencing your own stock photos, site administration may ask you to provide the proofs that you're the author of the photo (usually this is a photo in RAW format with proper meta tags). Inability to verify your authorship will result in rejection of the custom skin.

(What is RAW with Meta tags exactly? Sorry if this is a dumb question but like I said im new to this.)

• You can't use textures, complex brushes, styles and other application resources which are not created by you.

(So I hve to make my own brush or can I use genaric brushes provided by my photo editor?) 

First one.

RAW format as defined by Google:

A camera raw image file contains minimally processed data from the image sensor of either a digital camera, image scanner, or motion picture film scanner. Raw files are named so because they are not yet processed and therefore are not ready to be printed or edited with a bitmap graphics editor.

Meta Tags as defined by Google:
Meta tags are one piece in a large algorithmic puzzle that major search engines look at when deciding which results are relevant to show users who have typed in a search query.

Im not sure what it is either, but maybe this will help. I guess if a search comes up with those images and its not yours then it will be rejected. But if it is not found online (unless you submitted it on DA or something) then it would be yours. Maybe? I am not sure really.

Second one.

I am pretty sure you can use the brushes that did come with the program.  I do on GIMP with pencil and paintbrush, and sometimes use the spot brushes.

Someone will probably come up after me to fill in the info you still need or to confirm/deney mine.

Thanks! That helps some anyways. 

1) In case if a photo can be found through image search services, we may ask for proofs that you're the original author. There are usually two ways to prove the authorship: providing an unedited source photo with preserved meta tags (basically this is an unedited image that your camera outputs when you make a shot) if that source can't be found online, and providing the close shots of the same object / event, made a moment earlier or later, if they can't be found online as well.

2) Usually you may use any default resources that you graphic software provides.Just try to avoid complex resources that may be an object of copyright (like a brush in the form of wings, a tree, a tribal tattoo etc.).

1) Also, I recommend using your own photos! Most of my horse skins, and some of my dragons, are actually based off of my photos of horses or the sketches that I have taken of horses while at the stable I visit. It's quite fun to get a singular pose off of several photos. I know Deviantart has lots of great resources on this! And how to sketch from photos (upside-down method anyone??!)

2) Making your own brushes is fun too! Deviantart, once again, has great tutorials on this for your programs! I sometimes make a brush based on a photo I took! It can take a bit of practice, but is so worth it. I literally have jillions of brushes on my computer. But I have my favorites (about 6 of them) on my favorites. Most are soft edge brushes, some texture brushes, and some I use for lineart. 

I know I have some artist friends who have allowed me the use of their brushes and vice versa. Some artists on deviantart also allow their brushes to be used in any environment without credit (though it is ALWAYS a good idea to check with the artist). But most will not let you use them in a way that gives you monetary gain. So be sure to check if you do go this route. 

Patterned brushes are repetitive and take away from the complexity of the drawing. It is almost too perfect. When I first started... *blush* I used them in my art: http://icemask.deviantart.com/art/Commision-Nicole-Penny-Horse-64521399

(Ewwwww!) Don't judge me too harshly, this was 2007 after all!! 

Now-a-days I can get so far on just a few soft edged brushes. Then again I work in an odd way: http://justchasingfireflies.deviantart.com/art/Edra-532919929

So honestly, if you do go the "basic route" you can get nice results. It takes lots of time (I'm a good example... a little over 9 years now. Then again I have no artistic background or education at all). Deviant art, like I said, has GREAT tutorials!!!