Give peas a chance
Join Date: May 2007
Location: California, USA
You would need a page layout program such as Indesign or Publisher, as well as the ability to create a PDF from that file. Those programs allow you to create posters that feature both photos and text. You can then upload the PDF to a banner maker. It's a pretty common business, but you may want to choose one that is local to you in order to save on postage. Hand-painting a poster is an option too, if you don't need to include photos. Most banner printers also offer design services... in case you don't want to deal with those programs.
Personally, I prefer banners over posters, because they can fold up and are easy to carry. You can have posters printed on cardboard or corrugate plastic. The plastic is more durable and might be a good idea if you would like to use it over and over again. You might want to keep in mind any local regulations concerning posters. For instance, where I'm at, demonstrators aren't allowed to attach wood sticks of a certain thickness to signs, because they could be easily converted into weapons.
Vegan Cookbooks Illustrated