I think that imagehyper is best choice, cover many locations and have higher payouts, anyways i never tryed it bymyself, i used imageporter only.
Pay ratios of imgchili, imageporter and imagehyper.

imgchili.com
Zone A --> $2.60
Zone B --> $1.00
Zone C --> $0.20
Zone D --> $0.10

A: Australia, Canada, United Kingdom, United States

B: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, New Zealand, Norway, Portugal, Spain, Sweden, Switzerland

C: Cyprus, Czech Republic, Estonia, Hungary, Israel, Japan, Latvia, Lithuania, Poland, Russia, Slovakia
imageporter.com
Tier 1 - 2.20 Points Per Unique View (2.60$ Per 1000 Unique Views)
Tier 2 - 0.90 Points Per Unique View (0.90$ Per 1000 Unique Views)
Tier 3 - 0.10 Points Per Unique View (0.10$ Per 1000 Unique Views)
1 point = 0.001$
Tier 1 - United States, United Kingdom, Canada.
Tier 2 - Austria, Belgium, Switzerland, Germany, Spain, Italy, Netherlands, Greece,Ireland, Iceland, Lichenstein, Luxembourg, France.
Tier 3 - Portugal, Norway, Sweden, Finland, Australia, Japan, India, Hong Kong, Denmark, Finland, Monaco, and New Zealand.
imagehyper.com
3.00$ United States, United Kingdom, Canada, Australia
1.20$ Austria, Belgium, Switzerland, Germany, Spain, Italy, Netherlands, Greece,Ireland, Iceland, Lichenstein, Luxembourg, France, New Zealand
0.30$ Portugal, Norway, Sweden, Finland, Japan, India, Denmark,Hong Kong, Monaco
0.01$ All other countries
Rates quotes are for NSFW - XXX images