Hi Luke, we're really excited about image services and plan to support them during Q1 of this year. When you talk about downloads, what formats are you looking for? Would options of jpg, png and tiff suffice?
General caveat: we are an agile team and development schedules are subject to change at any time.
I agree with Luke, Definitely Tiff, but I'm also thinking file geodatabase with ESRI's Grid format. What do you think?
I have also requested the opinion of my scientists who are looking to publish out their raster data and should hear back from them in about a week or so.
Having imagery served through Open Data would definitely save us time. At the moment, these requests have to be done manually (don't get too many though).
I think tiff, jpeg and png would all be needed by various clients so it would be good to have all options available.