How to Photograph Art With Your Phone
This video uses an app called snapseed. This app allows you to do all the image editing on your phone. However, you can also use many other apps, including photo editing apps that are included with your phone. For more advanced editing use photoshop on your computers. With photoshop you can change backgrounds, edit very specific areas, etc.
For simple and cost effective lighting solutions, take your photos outside on a cloudy day. Sunlight filtered through the clouds offers the same effect as an expensive light diffuser. Diffused sunlight will ensure that no high key shadows will distort your documentation. Even lighting is one of the keys to the most accurate photos and the best documentation of color. Combining a cloudy day with a cheap tripod, and basic photo editing will give you excellent images for your website.