iStockPhoto was the first agency in my microstock experience. I started to submit pictures there in late November 2007 and continue within the upload limit of 15 pictures/week. With acceptance rate close to 70% I reached 337 pictures in my portfolio (September 20, 2008) and 485 downloads. My sell-through-rate at iStock is 38.5% and is slowly growing.

The plot above displays my hard work in developing this portfolio. Unfortunately, the number of downloads doesn't follow that growth and stabilized around May. Nevertheless, iStock is my top earner with 40.1% share of my microstock income. So far, I've got $400 in payments.

Here are the best selling pictures:

1. Gas prices
at a pump in Colorado

This is the most successful picture in my stock overall, submitted in February 2008, 39 downloads, more than $40 royalties. It is also selling well on Shutterstock and other sites.

2. Cryptex

My first bestseller online since December, 2007, and still doing well - 35 downloads and close to $30 in royalties. Other versions of this pictures (better in my opinion) are much less popular.

3. Broccoli sprouts

One of my macro shots, 31 downloads since February. For all my macro and product work I am using Canon EFs 60 mm macro lens which is my favorite lens in general.

4. Alfalfa sprouts

Another "green" macro shot, 25 downloads since January.

5. Excavator arm and scoop
digging dirt

Under influence of microstock I am paying more attention to industrial subjects like this machine at a road construction - 23 downloads since February.

6.Sewage

Processed and cleaned sewage flowing out of water reclamation facility in Fort Collins - 22 downloads since February.

7. Scoop of granola

One picture from my scoop series - 19 downloads including one extended license since February.

I am shooting some isolated objects with clipping paths, but they didn't make to the first seven. The isolated picture of an English saddle in my number 9. I don't have any people shots in my portfolio except one or two kayaking self portraits.

Perhaps, it's time to change something in pictures I am shooting. Quality? Subjects? With a weekly upload limit at iStock I don't see other way to drastically improve my results there. You are welcome to see all my iStock pictures sorted by the number of downloads.

Related posts and links:

• What Sells in Microstock? My List of Picture Bestsellers
• iStock most popular files
• Microstock Photography Earnings in 2008:
  August | July | June | May | April | March | February | January
• My microstock referral links for photographers:
  Dreamstime, ShutterStock, Fotolia, BigStockPhoto, 123RF, FeaturePics
• Reaching 250 Downloads from iStock with the Devil's Backbone Picture
• Organizing My iStock Pictures into Lightboxes
• First $100 Earnings from My iStockphoto Portfolio