Walmart-more compassionate about society OR just trying to fool the public?

You should know which of the above I believe in about Walmart's recent push to improve its public image by newspaper and tv ads, donating to journalism schools and sponsoring an ABC news segment.
One thing that can't be denied is that giant chain stores like Walmart are only increasing in popularity and presence. Whether that's such a good thing is one that I'm very uncertain about.
And I am aware that poor people can afford much more at Walmart at most other stores.