I personally don't think you need a card at all. Getting a bigger card and switching to a DVI input probably isn't going to make your pictures on your computer look any better. As long as the computer displays at the resolution you need and doesn't hang a bigger card will not change anything as far as how it looks. It might load faster though, not sure if loading static pictures is a function of the graphics processor or the main processor.
And I have both DVI and VGA systems and like said before for static pictures I can't tell a difference in picture quality from one to the other.
What a better video card is going to help with is more for gaming and video. It will help with motion and shading. Static pictures really are not that hard for a computer to display.
What you may want to check is that you have the computer set to the correct resolution for your screen. LCD screens display in a native resolution. Its not like the old CRT monitors that would display any resolution you fed them. The LCD has to upconvert or down convert any signal that is not its native resolution. Some tvs do a fairly decent job of this, but from what I have seen most computer monitors suck at it. So find out what resolution your screen is supposed to be and make sure this is what your computer is set to. Now if for some reason your computer won't go to that setting in 16 or 32 million colors then you will need a better video card. I honestly don't see that happening though unless you have a huge monitor.
The next thing I would look into is a quality monitor. This is what displays your pictures after all. If the monitor you have isn't all that great then no matter what you do to the computer it is your limiting factor. And incase your wondering the old CRT screens were actually better visually. If you have an older LCD screen I highly suggest looking at some of the newer ones by well known makers ( NOT AOC!)
Another thing you can do is try to calibrate your monitor like you would a home theatre tv. So it has the correct brightness, contrast and color. You can get most of the test signals online and the basic menu controls should get you pretty close.
So my honest opinion is you should be shopping for a quality monitor, not a bigger video card. And if you wanted to get a card and monitor DVI would not hurt. You can get a simple video card that does dvi pretty cheap. The monitor is what will cost you.
