There's Art Sytems:
http://www.artsystems.com - the Studio editioni seems to be what an artist would choose. But, I don't know if it tracks any financial information.
QuickBooks, of course, is good for tracking the financial, but may not give the ability to track all the information you'd want for a client and artwork.
There is a version of QuickBooks and a version of ACT that "speak" to each other and I think that's a superb feature. ACT is a very strong database program for tracking clients and prospects and is very customizable. I've been using it for years and I love it. You can add notes for acitivities, such as mailings, phone calls, emails. You can also set up reminders on certain dates - for example if you want to call a person on a certain date. If you use Outlook Express and maybe Outlook too, you can click the person's email from their record and the email window will come up. You can also create "groups" - I have such groups defined as Art Societies, Portrait Reps, Clients...etc. Then I can choose a group and send a mailing to everyone in that group. You can also send out form letters and print address labels. However, I've not found a way to enter an image, so if you wanted to enter the image of the painting, I don't think ACT does that.
Then there's WorkingArtist.com - you can download a trial version of it. I did so many, many years ago and found it was rather difficult to use. But, I would think they've probably vastly improved it since then. I doubt that it's as high-powered as ACT, but it's more artist oriented. ACT is a contact management system.