eBooks while selling for less have the potential of bringing in top dollar.
For starters Indie is short for Independent. Basically, that is a person who has chosen to write and publish their books apart from traditional or even so-called self-publishing venues. It is a person who is going the DIY (Do It Yourself) route.
Different publishers have different criteria for your book covers. We use the criteria that KDP requires. When we are working with an author, we point out that when using the Kindle Direct Publishing platform, you have access to templates that come with pictures or you can provide your own. If you are using the proper dimensions, the picture will fit within their templates forming a great cover.