Wellcome aboard
For your questions I'll try to give you some of my knwoledge.
On the main site there is a thread called parts sheet and there is a "drawing" of some common parts, like railings and other suff. On it (just to the right of the crane) there are three squared, which are the standard Shipbucket colors
Equipment
The height of a ships deck depends on the ship, but an 8 feet high dech is 16 pixels (according to the SB scale)
To draw you can use MS-Paint or Paint.net or any other drawing tool. I use MS-Paint.
To upload drawings you'll need an account in one of the image-hosting services, like Photobucket
How to upload from Photobucket, or Image host
How to use Imagehost, or Imageshack aor any other.
These two tutorials also answer your question about image size and format 1MB size and .PNG format or .GIF (I think most of us use .PNG now).
You don't need Photobucket Premium, I don't have it and I've almost never had problems (*make signs to ward evil-eye*)
Many linedrawings can be found on the web, but you can use books about ships which have linedrawings and scan them, and ofcourse you can ask for help on the forum.
My last answer should have been the first, but none the less here it is
Here you can find everything you'll need to know about Shipbicket
_________________
Thank you Kim for the crest
"Never fear to try on something new. Remember that the Titanic was built by professionals, and the Ark by an amateur"