Never use bad images on your printed materials and online. By "bad" I mean doing what I've seen many artists do (really truly): They stand in front of their already framed and under glass work with a cell phone (or other) camera, snap a picture, and use it on their websites and printed materials. Ack!!!
Totally okay if your art is to take photos with a cell phone. But that's not what I'm talking about. By "bad" I also mean dragging the thing out into the living room, shining a light on it, and then cropping the skewed image in Photoshop to make it look square. Double ack!!
You're an artist, it's all about your art. Why oh why would you want an image of it that is less than absolutely fabulous? Think of it this way: Would you want your work displayed at a gallery with no lighting on your artwork, where they hang your work far below or far above eye level, where they make everyone stand to the side, and view the work from behind dirty tinted glass? Well, that's what you're making them do when you use poor images of your work in your printed materials and online.
Everything you do in your art business starts with great images. Everything. Professional, quality images and scans.
I'm not saying spend a fortune, just spend enough to get a great image. You can do it yourself IF you know what you're doing (you have the skills of a professional photographer), or save the time and angst and have a photographer or an artwork scanning service do it. Remember about the opportunity cost. It costs something to save a few bucks (like your time in the studio, time with your family, missed opportunities.) If you're not in this to become a professional photographer, maybe it's better left to the pros, ya know.
Read this article about photographing artwork.
Search amazon for books on the subject.
Get info on artwork scans, start with Digital Arts Studio because we know and respect them.
Hire ME to help you decide. Artists do it all the time. You can even get a complimentary 15-minute consultation, or an in-depth consultation costs only $55 (up to 45 minutes on the phone) and you can pick my brain and get your questions answered.
Also, write to me if you have questions and I'll cover them in upcoming tips (firstname.lastname@example.org).