How would I create a mosaic starting on one image and then zooming out to be someones face?

Thank you all for the help!

If you don't have enough experience this animated mosaic effect, just do a quick search on google and you will find  lot of ready made template allow you to create this in few minutes.

I don't think illustrator would work for it because that's for vector work.

You could use After Effects for creating the mosaic but it might be tedious done manually, unless there's a way of scripting the positioning of each photo (if it's made up of many photos). Other software (such as Studio Artist 5) that has a mosaic option would make the creation of the mosaic easier, and you could still create the animation of the zooming out etc. in After Effects. Though creating it with other software would create a huge image - you might want to add layers with the initial image(s) separately in After Effects (eg. placed over the position of the output of the image software - maybe like suggested previously) so the image you start on (in closeup) can be clear without having to use a very big mosaic image. It could also be done if you can use a programming language (eg. going through each of the mosaic piece images looking for the one that is closest in average rgb values to the different points on the image. Or a more accurate/slower way that looks through scaled down versions of the  pieces, comparing the rgb differences with those of the image you want to make the mosaic out of and picking the one with the least rgb difference).

Totally irrelevant where you are doing your photo mosaic. Illustrator has no magic and doesn't automatically turn pixel-based photos into vector artwork and surely you don't care to do so for potentially hundreds and thousands of images, even more so since it's not necessary nor practically feasible. The rest is just a matter of finding a suitable photo mosaic software and using its output as template to rebuild the mosaic in AE and mix it with whatever animation you fancy plus of course struggling with the inherent limitations of the process like those tons of images consuming all memory and bringing AE to its knees...

Mylenium