Hi,
This is Matt Cutt's view on the subject:
"The other thing that happens is that people don’t always realize what they are linking to when they reprint these infographics. Often the link goes to a completely unrelated site, and one that they don’t mean to endorse. Conceptually, what happens is they really buy into publishing the infographic, and agree to include the link, but they don’t actually care about what it links to. From our perspective this is not what a link is meant to be."
...
"This is similar to what people do with widgets as you and I have talked about in the past. I would not be surprised if at some point in the future we did not start to discount these infographic-type links to a degree. The link is often embedded in the infographic in a way that people don’t realize, vs. a true endorsement of your site."
http://www.stonetemple.com/matt-cutts-and-eric-talk-about-what-makes-a-quality-site/
Google doesn't want to count links when people are posting them because it comes with the code - they want links to be an endorsement of the site. My recommendation is always to allow people to turn the links off in some fashion, whether we're talking about "powered by" links, widgets, or infographics.
In your case, you could have two different code snippets: one that includes a link back to your site, and another that is either missing a link or nofollowed. I'd think it's totally fair to get links by creating something people want, especially if they have the option to turn it off. You can encourage people to share your site or "ink to the source, but "forcing" them to do so might someday result in links being devalued.