John Singer Sargent
http://images.google.com/images?source=ig&hl=en&rlz=&q=john+singer+sargent+portraits&um=1&ie=UTF-8&ei=d3u2Sp6CG4eKsAOmzfQC&sa=X&oi=image_result_group&ct=title&resnum=1
http://jssgallery.org/thumbnails/Sargent_Paintings_Index.htm

Celia Beaux
http://images.google.com/images?hl=en&um=1&sa=3&q=celia+beaux+portrait+paintings&btnG=Search+images

Juaquin Sorolla
http://images.google.com/images?hl=en&um=1&sa=1&q=j+sorolla+portraits&btnG=Search+images&aq=f&oq=&aqi=&start=0

John Everett Millais
http://images.google.com/images?hl=en&q=millais+portraits&um=1&ie=UTF-8&ei=PXy2So-cC4eKsAOmzfQC&sa=X&oi=image_result_group&ct=title&resnum=1

Anders Zorn
http://images.google.com/images?hl=en&um=1&sa=1&q=Zorn+portraits&btnG=Search+images&aq=f&oq=&aqi=&start=0

Richard Schmid
http://www.worldofportraitpainting.com/masterpieces/schmid-nan.htm
http://www.richardschmid.com/gallery2_page.htm

Jeremy Lipking
http://images.google.com/images?hl=en&um=1&sa=1&q=jeremy+lipking+paintings&btnG=Search+images&aq=f&oq=&aqi=&start=0
http://www.lipking.com

Casey Baugh
http://caseybaughfineart.com/

Tony Pro
http://www.tonypro-fineart.com/#/portraits/4518001871

Ilya Repin
http://images.google.com/images?hl=en&um=1&sa=3&q=Ilya+Repin+paintings&btnG=Search+images

Scott Burdick
http://images.google.com/images?hl=en&q=scott%20burdick%20paintings&um=1&ie=UTF-8&sa=N&tab=wi
http://www.burdicklyon.com/

Valentin Serov
http://images.google.com/images?gbv=2&hl=en&ei=Ho62Sp_LDpHutgOWu4zSDA&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=serov+portrait+paintings&spell=1&start=0

Henry Yan
http://www.henryyanart.com/?board=painting

Morgan Weistling
http://images.google.com/images?hl=en&um=1&sa=1&q=morgan+weistling+paintings&btnG=Search+images&aq=f&oq=&aqi=&start=0
http://www.morganweistling.com

Zhaoming Wu
http://www.zhaomingwu.com/
References :