http://oranamxi.deviantart.com/art/I-love-Pixels-Background-435857628?ga_submit_new=10%253A1393058252 here's a background i made.

I use a program called gaphicsgale. http://www.humanbalance.net/gale/us/

i really couldn't help but to laugh because of the dinosaur :3
but its pretty cool

Everything looks better with a party hat :D

I recommend using pixel tools for making pixels in flash. Here is a tut.
http://code.tutsplus.com/tutorials/creating-pixel-art-in-flash-using-pixel-tools-v20--active-6448

http://www.humanbalance.net/gale/us/ <-- GraphicsGale is far superior...it has a 1x1 pixel grille, movement from one pixel to the other with the arrow keys, etc, you can read more on the website. The only program that comes close to being as good as ale is Adobe Photoshop.