Google has recently started indexing Flash, at least in some instances. AFAIK, they cannot extract text that's displayed within a graphic such as a JPEG or GIF. And I wouldn't count on that happening any time soon, FWIW.
They will at least in some cases use the image ALT attribute as a substitute for text. I know they do this when the image is a link (i.e. part of a graphical menu, for instance). Sometimes they do this when the image is not a link, sometimes they don't. I'm honestly not sure which way they're going with that at this precise moment. So it's possible -- likely even -- the image ALT text would be indexed and counted, but I wouldn't necessarily depend 100% on the ALT text of non-link images helping out in every instance.
As to getting a first page ranking, I'm assuming you don't want to slide over into black hat techniques. Staying on the "white hat" side, it can be done, but it would depend a LOT on the phrase you're targeting for that page.
I think anything even moderately competitive would probably require a massive number of links (or at least a good handful of exceptionally powerful links) to make up for the near total lack of on-page text. Much beyond that in competitiveness, and you're looking at a really tough slog. For highly competitive phrases, I'd say you might as well forget it without any significant text on the page.
IMO, the client needs to understand they're basically asking you to work with one hand tied behind your back and adjust their expectations accordingly.
Diane Aull - NineYards.com
: Helping Businesses Do Business Online
Whether you think you can, or that you can't, you are usually right.