In a recent blog, Matt cuts from Google has said…

“You can’t have too much content on your home page, I wouldn’t have a homepage that has 20Mb on it, that takes a long time to download and user that are a dial up or modem…slow connection, they’ll get angry at you, but in general, if you have more content on a home page there is more text for Google to find.

So, rather than just pictures for example, you have pictures plus caption plus text because a little bit of textual information can go a long way. I have had anywhere between 500 and 1000 word on my front pages, I (Matt Cutts’) tends to veer towards a bit more content when possible.

Hope that helps.