One thing I keep hearing in the message boards on Dreamstime is the idea of quality versus quantity as it relates to DPI (downloads per image). Contributors with high DPI are seen to be more successful per image, but also attributed the honor badge of 'quality'. Does this mean if you have a low DPI you aren't uploading quality? NO!
The thing is, DPI is only affected by two factors - the number of online images and the number of sold files. Let's analyze what affects this number and how you can change it:
1. Time. The longer you are selling images, the higher your DPI. Keeping everything else constant every sales contributes to making your DPI higher. While we can't increase how long we've been doing stock other than waiting, you will notice that most poeple with high DPI have been doing it for a while (2005-2007).
2. Images online. When you upload new images, you instantly knock your DPI down. If I had 1000 sales with 250 images people would say I had a high DPI and a quality portfolio. I could then upload 250 new images and my DPI would drop in half. That says nothing about the quality of my portfolio, and in fact my (previous) DPI on the older images shows that I'm likely to sell the new images well too. As I will show, stopping uploading is the fastest way to boost DPI, but the worst choice in terms of revenue. Note the opposite is also possible - you can cull non-sellers out of your portfolio, boosting your DPI (with no new sales!). Does this add quality? Yes, but also shows how a contributor can artificially make it appear they had good up front selection (to anyone looking solely at their DPI with no history). I could seriously boost my DPI if I pulled out 500 non-selling images - but I don't know which will succeed later!
3. Sales. There is no doubt that a portfolio with high sales has something going for it. I question the use of the word 'quality', though. More often it is a niche that someone has hit. I see high DPI in small portfolios of a single topic. Could these contributors continue to upload on the same topic and increase sales? Probably not - they've focussed on their best shots already. Adding more of the same dilutes sales. I gauge my sales success on my monthly sales per 100 images online. This seems to remain pretty constant for me, and shows what my ability to generates sales from a given number of uploads is. I get about 20-25 sales per month on 100 onlines files. This is a number specific to Dreamstime, and not that important in many ways (say revenue) since a given site with higher sales may have lower royalties, etc. But it is relevant to DPI.
4. Depth of the sales. Most of the small portfolios I've seen with high DPI are by people who started early in stock and stopped uploading. This is the recipe for high DPI - get in early (so sales trickle in and boost DPI), stop uploading so you don't knock it back down.
5. Luck. A good article from the master of stock, Yuri Arcurs, says that he can predict "40-50 percent of sales, max". So even the master of quality (large format, quality equipment, quality lighting, models, experience) still says he can't predict which will sell. So I think luck really comes into it. You'll find in people with high DPI that many with small portfolios have a very small number of images with large sales, and the rest don't do well. In other words, they got lucky or deliberately delivered on something buyers really needed.
So what do I call quality? A large portfolio (> 1,000) with steady uploads where both new and old images contribute to a moderate DPI (2-5). Arcurs has both of those, plus a high DPI. But consider how high sales on a portfolio with 25,000 images continues to add to the DPI despite uploading 800 new images a month. That is almost the exact rate I'm adding to my portfolio! Also, a portfolio where the popular images go beyond the first few images says 'quality' to me...
Finally, an example (I'm making some assumptions based on my experience). Consider two contributors with the same mysterious ability to deliver on quality (sales). They both get 25 sales a month for every 100 files online. They continue to upload for a year adding 25 images a month. At the end of year 1 they both have 300 images, and a DPI of 1.6 (487 sales). Contributor 1 says "I'm doing great" and stops uploading. Sales continue and by the end of year two she has added another 900 sales, ending up with a DPI of 4.6. Contributor 2 continues to sell and still uploads another 25 a month ending year two with 600 online. Contributor 2 has a lower DPI of 3.1, but generates twice the sales. I would argue they have exactly the same 'quality' or ability to generate sales, but the resulting DPI is totally different. If contributor 1 had started a year earlier, total sales and DPI would be even higher!
Bottom line, I don't think a high DPI is the final word on a contributors quality!