To be proud of something I think, is to be content with it, or unashamed of it, without the need to obtain praise from others or to praise yourself to others.
To be prideful I think, is when you are proud of something and desire others to praise your efforts. Also when you feel the need to praise your own efforts to others is being prideful.
Proverbs 29:23 ESV One's pride will bring him low, but he who is lowly in spirit will obtain honor.
Proverbs 27:2 ESV Let another praise you, and not your own mouth; a stranger, and not your own lips.
1 John 2:16 ESV For all that is in the world—the desires of the flesh and the desires of the eyes and pride in possessions—is not from the Father but is from the world.
I'm certainly not saying we shouldn't, as artist, share our works. After all, many of us need to make a living selling our art and to sell we must put it out there for the world to see. The ability to create art is a God given talent, whether you believe in God or not. That's something I try and keep in the forefront of my mind with every painting I do. My art does not need to be "Christian" in nature, so long as what I do paint I paint to glorify God. Humbly and to the best of my abilities.
9" x 12" Pastel