Revelations from the ugliest design book ever, and a personal question

In addition to my IDD major here at Quinnipiac University, I have undertaken a minor is business management (BM). Originally this decision was something of a ‘fail safe’ should my abilities as a designer not develop, based on the advise of my father that “any degree in business is useful”. Fortunately my design skills have progressively matured and my BM minor has taken a permanent supplementary role to my future design career.
Recently however, I have been apprehensive with my decision to go into BM; wishing instead that I had chosen a marketing minor. My recent foray into the working world with my winter internship at Healthtrax Wellness & Fitness in Glastonbury CT had me working almost exclusively with the marketing team. In fact, in this particular corporation the design team seemed to serve as an adjunct to the marketing department. I reasoned then that possessing marketing skills would be a valuable asset in acquiring a job and working effectively within a company. Unfortunately hindsight graced with me with its clarity far too late into my academic career, and I did not have the ability to change my minor.
The reason I am posting about this personal experience is that the book “How to be a graphic designer without loosing your soul”, changed my feelings of missed opportunities to ones of encouragement again. Specifically in chapter five, the author Adrian Shaughnessy, spoke about the need of all designers to function well within a team, both as a leader and follower. Essentially Adrian was talking about the need for an understanding of team dynamics in terms of conflict, trust and high levels of emotional intelligence; the focal points of BM. The relief I felt after reading this chapter was immense as the sensation of missed opportunity left my psyche. Adding to this personal victory I so enjoyed, Adrian failed to mention anything in depth about marketing (though it would not surprise me if this came up in later chapters).
The second part of this blog has to do with a personal dilemma over a software package I discovered during an Image search on Google. Called ‘Arsenal, Professional Design Weaponry’, a series of software packages from GoMedia, this various sets contain a series of intense vector images that really relate well to the graphical style that interests me the most. Best described as a grunge in style with certain PUNK rock elements the software packages allow the user to create intense visual designs using a series of designs created by other artists.
My dilemma in this is that, by using this pre-rendered images am I lowering the authenticity of my own work? I almost feel as though it undermines the originality of my work, even if it allows me to create the designs I want in a vastly more efficient.
The counter argument to this is that I already do this in other programs, such as Photoshop, where I manipulate images taken by other photographers. Would using the pictures rendered by artists be any different? I’m certainly not a photographer, which is why I have to download images from iStockPhotos. I’m also not an artists, I can sketch and given time can recreate examples of the work contained within the Arsenal software, but it takes a great deal of time. In summary, I feel stuck between a fear of loss of the authenticity of my work versus the expedience offered by Arsenal. Any input would be greatly appreciated.