I'm aware of two programs that will show you paint colors on a house before purchasing.
1) <a href="//www.benjaminmoore.com/bmpsweb/portals/bmps.portal;jsessionid=60FpLg5DqWXPtcDhHKhtTh3Hv01Z6Vc02qrcSDMRQMkLvkhk6YJJ!-1193605091!1937216709?_nfpb=true&_windowLabel=portletInstance_2&portletInstance_2_actionOverride=%2Fbm%2Fcms%2FContentRenderer%2FrenderContent&portletInstance_2cnp=public_site%2Farticles%2Fmain_page_articles%2Ffh_home&portletInstance_2np=public_site%2Farticles%2Fapplication_article%2Fapp_personal_color_viewer&_pageLabel=fh_home" rel="nofollow" target="_blank">Benjamin Moore's Personal Color Viewer</a> – The online version won't let you load your own photo, but works well. They also sell a "Pro" version for $10 that you load on your own computer and it does let you use your own photos.
2) <a href="//www.sherwin-williams.com/do_it_yourself/paint_colors/paint_color_palette/" rel="nofollow" target="_blank">Sherwin Williams Color Visualizer</a> – This one doesn't allow the uploading of your own photo. But, it does have several preset rooms or exterior images that you can 'paint'.
Both of these program work well, but only show paint colors offered by each manufacturer. Give then a try.