I couldnt get that solution working the way i would like it to. Because I wasnt able to exclude Images, it just showed all Images that were on those Posts ( possibly because of the type of galery or sitestructure that I have going).
However: I am now using the “Page Links To”-Plugin by Mark Jaquith to set up Posts that use the FeatureImage that I want to show up in the search, and then uppon klicking, it redirects to the original Post.
This seems to be working very well with your Plugin!