attachment_fu - convert an image to 8-bit text

hi all

I'm using attachment_fu to handle a bunch of uploaded images (jpgs). I have a controller where i want to send two images in the response, converted to 8 bit text, all in one string, like

render :text => "LOGO1=<bunch of text>,LOGO2=<another bunch of text>"

Can i do this conversion in a simple way with attachment_fu? Or by some other method?

thanks max